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LIBRARY OF CONGRESS. 

Chap..i^ Copyright No_ 

Shell-j. $84 

UNITED STATES OF AMERICA. 
























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MECHANICAL ACHIEVEMENTS OF THE XIX. CENTURY 









STEVE INS’ 


Mechanical Catechism 

FOR 

STATIONARY AND MARINE ENGINEERS, FIREMEN, 
ELECTRICIANS, MOTOR-MEN, ICE-MACHINE 
MEN AND MECHANICS IN GENERAL 

PRACTICAL KNOWLEDGE 

IN EVERY BRANCH OF MECHANICAL INDUSTRY 








Full Information on Water, Steam, Fire, Smoke, Electricity, Horse- 
Power, Refrigeration, Liquid Air. Exact Description of, and Directions 
for the Care of Boilers, Grates, Engines, Slide Valve, Safety 
Valves, Injectors, Pumps, Steam Gauges, Lubricators, Eccen¬ 
tric, Link Motion, Indicator, Ammonia Compressor Brine and 
Direct Expansion Systems, Lathe, Tools, Dynamo, Batteries, 
Parallel and Series Wiring, Three-Wire System, Motors, 
Controller, Electric Heating, House Wiring, Traction 
Engine. Thorough Instruction in Calculation of Horse- 
Power, Pulley-Speed, Lathe-Gearing Square Root, 
Leverage, Tensile Strength, etc. Introduction to 
Algebra. Systematic descriptions alternate 
with elaborate sets of Questions and An¬ 
swers in plainest English. Numerous tables 
and original diagrams make the book 
interesting as well as instructive. 

Valuable Recipes and Hints for all 
sorts of Emergencies, many of them 
especially selected for this work. 


OVER 240 SECTIONAL CUTS AND ILLUSTRATIONS 


BV 

H. G. STEVENS, M.B.E. 


Copyright 1899, by WM. H. LEE 


CHICAGO 
LAIRD & LEE 

1S99 




TABLE OF CONTENTS 


The Alphabetical Index, pages 5-9, gives subjects in detail. 

28658 



PAGE 

Water. 11 

Steam. 16 

Combustion and Firing.. 19 
Locomotive firing. 29 

Boilers. 33 

Rivets, Braces and Stays 33 

Plant appliances. 38 

Boiler explosions. 46 

Running a boiler. 49 

Steam heating.. 52 

Smoke and chimney.... 53 

Brickwork. .'54 

Boiler testing. 56 

Boiler horse-power. 57 

Feed water heater. 59 

Tensile strength. 60 

Safety Valves. 62 

Injectors . 69 

Feed Pumps. 73 

Steam Gauges. 89 

Lubricators. 91 

The Engine. 96 

Valve setting. 97 

Reversing. 100 

Lead and lap. 102 

rwo aoNSMUiMte 104 

stop. . 107 

Hot air eugiEe. 109 

Condensers.-,'x.>K... 112 

LThe eccentric ,y. ..L_ 116 

Dead centers.v\ ... 118 

| f Tyioing thF efi&ine.. J|?... 120 
111 uAtrtomatnfc gbvernor^j... 124 

Balanced slide valve_ 133 

Corliss engine^ftid gear. 135 

■ C^Vacuum dash pot. 140 

' '^^-Eevie w... :. . .. 141 

Link motion. 144 

Horse Power. 146 

Indicator. 154 

Pantograph. 160 

Review . 162 



PAGE 

Compressed Non-vib'r. 

Air Engine.:... 166 

Miscellaneous questions 

and answers.. 169 

Measurements and cal¬ 
culations . 175 

Mechanical Refriger¬ 
ation. 180 

Ammonia..'. 182 

Methods of refrigeration 185 
Water examinations.... 195 
Direct expansion system 197 

Ammonia tests, etc. 211 

Review . 219 

Liquid Air. 223 

Liquid hydrogen. 225 

The Machine Shop. 226 

The lathe. 228 

Twist drill grinding_ 231 

Polygonal nuts. 233 

Rules and Standard 

Numbers. 234 

General Useful 
Knowledge. 242 

Electricity. 249 

Dynamo and attach¬ 
ments.267 

Varieties of dynamo. 275 

Management.279 

Repairs . 287 

Measurements. 290 

Motors.297 

Controllers . 301 

Electric locomotive. 304 

Electric heating. 306 

Motor connections . 308 

Electric wiring. 309 

The Elements of Alge¬ 
bra .'.318 

The Traction Engine.. 324 
The Hay Stacker.332 

Journal Box Babbitt¬ 
ing. 335 































































INTRODUCTION 


Almost every day some new device is invented 
for saving labor or fuel or other material. Where 
so many brains, scientifically trained, and so many 
thousands of practiced eyes and hands combine to 
make human life more comfortable, by shifting an 
ever larger portion of the hard labor to the shoul¬ 
ders of Nature’s hidden forces, it is not strange 
that the engineer and machinist finds greater and 
greater demands made on his intelligence and 
experience. 

A widely-known machinist delights in repeating 
to his friends his account of a little incident that 
will illustrate our point. He happened to enter the 
office of a large factory, where one of the firm 
jumped at him and hustled him into the engine- 
room, where the men tending the machinery were 
standing idle and puzzled. Something was wrong! 
“Start her up,” said the proprietor. The big 
engine made two or three revolutions, giving a 
thump at each turn as if the fly wheel was about 
to go to pieces. “Stop her!” the machinist said, 
took the key of shaft and fly-wheel out, filed it 
down one sixty-fourth of an inch, and then drove it 
in place again—and she started up without a 
thump. “Well, I declare,” said the proprietor, 
“how much do I owe you?” “Twenty-five dollars 
and fifty cents.” “What’s that, sir—$25.50 for 
twenty minutes of your time?” “No, sir; 50 cents 
for my time and $25 for knowing just what to do. 
It’s worth that much to you, I dare say, to get 
your men to work, isn’t it?” The money was 
cheerfully paid. 

It’s the practical knowledge that tells; and 
to aid engineers and mechanics in general to do 
intelligent work is the desire and aim of 

The Author. 



LIST OF ILLUSTRATIONS 


PAGE 

Cross Compound Engine.. 10 

Ice Plant. 10 

Smoke prevention. 25 

Riveting.33, 34, 35 

Gusset stay. 36 

Steam fittings. 39 

Globe valve. 40 

Water column. 42 

Safety alarm. 43 

Boiler water line. 45 

Straightway valve. 50 

Boiler setting.54, 55 

Safety Pop and Muffler. .63, 64 

Safety valve (lever). 68 

Injector. 70 

Duplex pump. 76 

Check and gate valves.. .82, 83 

Artesian pump. 84 

Pump governor. 85 

Deep well pump and plun¬ 
ger. 88 

Steam Gauge . 89 

Double and Triple feed 

lubricators.91, 93 

Common slide valve and 

movements.96, 98, 100 

Tandem Comp'd Engine.. 106 
Corliss electric engine stop 108 

Hot air engine. .... 110 

Connecting rod and oilers 

.Ill, 112 

Concentric and eccentric.. 116 
Direct and indirect mo¬ 
tion. 117 

Slotted stick. 121 

Engine lining..122 

Automatic governors.. 125, 130 
Balanced slide valve.... 133, 134 
Corliss valve movements 

. 135, 136, 137 

Corliss cut-off gear. 138 

Vacuum dash pot. 140 

Dink motion. 144 

Indicator. 154, 155 

Indicator chart and dia¬ 
grams.156, 158, 159, 160 

Pantograph. 161 

Air engine. 167 

Crank pin travel.169, 170 

Dead center points. 172 


PAGE 

Ice machine. 184, 186 

Freezing tank. 192 

Ice can dumps. 194 

Compressor valve. 197 

Gas compressors.199, 201 

Ammonia liquefier.203 

Valves and fittings. 207 

Bye pass valve. 208 

Ammonia testing. 211 

Engineer’s and machin¬ 
ist’s tools. ... 226, 227 

Lathe and tools. 228, 230 

Twist drill grinding... .231, 232 

Area of circle... . 234 

Ventilation. 243 

Arc lamp. 255 

Incandescent lamp. 261 

Dynamo. 268 

Storage batteries.271,272 

Rheostat.272 

Transformer and brush 

pointer. 273 

Alternating dynamo. 276 

Generator panel. 279 

Feeder panel. 280 

Chemical meter. 295 

Stationary motor. 297 

Carbon Brush Holders.... 298 
Third rail motor trucks... 299 
Street car motor suspen¬ 
sion and motor truck.^00, 301 
Electric car controllers.... 302 

Electric locomotive. 304 

Electric Heating and Cook¬ 
ing . 307 

Stationary motor connec¬ 
tions . 308 

Wire joints. 314 

Traction engine. 324 

Coal and water tank. 325 

Curve turning device. 325 

Compensating gear.326 

Friction clutch fly wheel.. 326 

Cross head. 327 

Tandem compound cylin¬ 
ders.329 

Single eccentric reversing 330 

Reversing rack. 331 

Hay stacker gearing.. .332, 333 
Hay stacker.334 





































































ALPHABETICAL INDEX 

Note: For Electrical Terms see, also, Dictionary, page 253. 


PAGE 

Absorption method, ice.... 185 

Accidents by shafting. 245 

Accutnu ator. 271 

Air, a compound. 13 

*• chamber, Duty of_ 83 

“ Compressed—engine.. 166 

“ in combustion. 19 

“ Liquid. 223 

“ needed for fire. 23 

“ spaces in grates . 20 

“ Weight of. 13 

Alcohol expansion. 18 

Algebra, Elements of.. 318 

Alternating current. 252 

Ammonia . ..,... 182 

Boiling points of 210 

“ Charging. 217 

“ compressors. 184 

condenser ... 188, 202 

Discharging.219 

pump valve. 197 

“ tests.211 

“ valve and fittings 207 

Ampere. 291 

Ampere’s Rule. 252 

Appliances of steamplant. 38 

Area of circles. 235 

Artesian pump. 84 

Atmosphere, Weight of... 14 

Automatic gov., side crank 124 
“ self-contained. 129 

Babbitting a journal. 335 

Balanced slide valve. 133 

Ball turning. 229 

Band saw mending.168 

Barometer. 14 

Battery, Electric. 271 

“ of boilers. 51 

Belting, Cleaning of. . 248 

“ horsepower. 152 

Boiler, The. 33 

construction. 45 

“ explosions. 46 

“ How to clean. 49 

“ Safe-pressure. .. 176 

“ setting.40,54 

“ testing. 56 


PAGE 


Boilers, Battery of. 51 

Boiling, Definition of. 18 

Boiling points of ammonia 210 

Braces. 35 

Brine solutions, Table of . 195 

“ system... 190 

Brushes, Motor.298 

Brush holder. 273 

B. T. U. 293 

Bye pass valve. 207 

Calculations, Engine. 175 

“ of coal in bin. 248 

“ Pulley speed . 239 

“ Stay and bolt. 38 

Capacity of pump. 74 

Carbonic acid. 13 

Care of electric plant . 284 

Casing for electric wire... 316 

Cell, Daniell. 274 

“ Gravity. 274 

Cement for steam pipes... 222 

Charging ice machine. 217 

Check valve.81,83 

Chimney. 53 

Circuit, Arrangement of.. 314 

“ Short. 812 

Cleaning by steam. 247 

“ belts.248 

“ rusty steel. 247 

Clearance. 176 

Closed coil. 276 

Clutch, Friction.326 

Coal, Decomposition of... 21 

*• How it burns. 22 

Coal-bin calculations— 248 

Cold storage temperature. 206 

Color of flames. 20 

Combustion, Perfect. 19 

Commutator.270 

Compensating Gear. .325 

Compound engines .... 104, 328 
Compressed air engine... 166 
Compression method, ice . 187 
Compressor, Ammonia.... 197 
Condensation, Ammonia.. 188 
Condensers, Ammonia. 188, 202 
“ Jet.114 


5 



































































INDEX 


6 


Condensers, Open-air. 

Steam. 

“ Surface .... 

Conductivity. 

Connecting rod. 

Connections, Electric .... 
Constant potential service. 

Continuous current. 

Controller. 

Converter. 

Cooking, Electric. 

Corliss electric stop. 

“ Engine . 

Coulomb. 

Crankpin and crosshead 

travel. 

Crosshead at dead center.. 

“ of engine. 

Current, Alternating. 

“ Continuous. 

“ Multiphase. 

Cut-out, Electric. 

Cylinder dimensions. 

Daniellcell. 

Dash pot. 

Dead center. 

Deep well pi unger. 

“ “ pump . 

Diagram, Indicator. 

Dictionaiy. Electrical _ 

Differential gear. 

Dimensions of cylinders .. 
Direct expansion system.. 
Discharging Ammonia 

Pump . 

Distribution, Electric. 

Duplex gauge . 

Dyne.. ... 

Dynamo and its parts .... 

“ Care of.. 

“ Efficiency of. 

Repairs of.. 

Running a. 

“ Varieties of....... 

Eccentric.— 

“ How to set an... 

rod. 

“ Single-revers¬ 
ing . 100 , 

Efficiency of Dynamo. 

Electric locomotive. 

“ heating and cook¬ 
ing. 

“ measurements.... 


Electric wiring. 309 

Electricity, Chemical and 

thermal. 251 

“ Current and 

statical. .. . 250 
“ Frictional and 

voltaic. 250 

“ Positive and 

negative.... 249 

Elements of Algebra. 318 

Engine, The. 96 

“ Compound.104 

“ “ with 

single valve.... 328 

“ Compressed air . 166 

“ Corliss.135 

“ stop. Corliss elec. 107 

“ Cross compound 105 

“ crosshead. 327 

“ Electric . 304 

“ Hot-air pump’g. 109 

“ Lining. 120 

“ measurements.. 175 

“ pounding. 119 

“ Receiver.. 105 

“ striking points.. 122 

“ Tandem com¬ 
pound .105, 328 

“ Traction. 324 

Erg. 290 

Expansion, Ammonia. 188 

“ system, Direct 190 

Explosion of boilers. 46 

Feed of boilers. 43 

‘ ‘ regulation. 57 

Fire, Care of. 25 

1 engine. 83 

Firing. 19 

“ Locomotive. 29 

“ Stages of. 20 

Fittings, Heater andboil'r 39 

Flames, Color of. . 20 

“ Length of. 22 

Foaming. 50 

Forced draught. 22 

Friction clutch. 326 

Friction in water pipe.... 238 


“ “ Electric..303, 308 

Gaskets. 51 

Gas meter reading. 243 

Gauge, Comp'd ammonia. 90 

“ Duplex. 90 

“ Steam. 89 


204 

112 

113 

310 

122 

314 

278 

252 

301 

273 

306 

107 

135 

291 

169 

172 

327 

252 

252 

252 

316 

328 

274 

141 

118 

87 

87 

156 

253 

325 

328 

190 

219 

314 

90 

290 

267 

279 

293 

287 

283 

275 

116 

117 

97 

330 

293 

304 

306 

290 












































































INDEX 


7 


Gauge, Vacuum.89, 1 lr> 

Gear, Differential. 325 

“ Reversing. 330 

Gearing, Lathe.228 

“ Stacker.332 

Glass tube, How to cut.... 247 
Governor, Automatic, side 

crank.— 124 

“ Autom., self- 

contained .... 129 
Pump, Autom.. 85 
Graphite for steam-fitting. 240 

Grate, Airspaces in. 20 

Gravity cell.274 

Ground. 812 

Hard Water. 195 

Haystacker. 334 

Heat. 174 

“ Latent.18, 175 

“ Utilized. 23 

Heater, Feed Water. 59 

Heating, Electric. 306 

Horse power. 146 

“ Belting. 152 

“ Boiler. 150 


44 Compound 

engine.... 150 
44 Electric.. .. 292 

44 Evaporat’n.. 57 

44 for incand. 


lamp .293 

44 Heating sur¬ 
face.37, 148 

44 of traction 

engines . . 328 

44 ot waterfall. 147 

“ of water¬ 
wheel. 148 

“ Rating of... 149 

“ Steam con¬ 

sumption. 149 
“ Tubular 

boiler. 152 

House Wiring ... 309 

Hydrogen, Liquid .225 

Ice Making.. . 180 

Incand. Lamp, H. P. for... 293 

Indicator. 154 

card. 159 

“ diagram chart ... 156 

“ examination. 162 

“ with pantograph. 160 

Induction.. .250 

Injectors, Classes of. 71 


Injectors, Parts ol. 70 

“ Size of.. 7i 

“ Working of. 69 

Insulation. .311 

“ testing. 281 

Inverse ratio. 310 

Iron and steel.61, 128 

Joints, Electric . 314 

Journal babbitting. 335 

Kilowatt .148, 261 

Lamp sockets. 317 

Latent heat.18, 175 

Lathe gearing.228 

“ tools. 230 

Law of Ohm. 291 

Lap and lead.. 102 

Leather belting cleaned. 248 

“ H. P. 152 

Leverage..241 

“ in safety valves.. 66 

Lightning, What is. 251 

Lining an engine. 120 

Link motion. 144 

Liquid air. 223 

44 hydrogen. 225 

Lubricators, How to attach 92 

“ How to clean. 95 

“ How to run .. 93 

“ Triple sight.. 93 

“ Working of... 94 

Machine shop. 228 

Magnetic field. 250 

Measures and weights. 236 

Measurements, Engine.... 175 

“ Electric_ 290 

“ Chemical. 293 

“ Mechani¬ 
cal . 290 

Mending band saw. 168 

Meter, Gas.243 

“ Chemical.293 

“ Mechanical. 296 

Mineral water. 196 

Miner’s inch . 238 

Miscellaneous Q. and A.... 169 

Molecules. 174 

Motions, Direct and Indi¬ 
rect .. ..117 

“ of Crosshead .169, 172 

Motors, Stationary.297, 308 

“ Third rail.298 

“ Surface Road.300 




































































8 


INDEX 


Motor Brushes.273, 

“ Reversing.. 

Muffler, Safety Valve. 

Multiphase current. 

Multipliers, Standard. 

Nitrogen. 

“ Weight of. . 

Nuts, Polygonal. 

Ohm, Law of. 

Open coil. 

Over and under. 

Oxygen. 

u Weight of. 

“ in Combustion ... 

Pantograph. 

Parallel connection. 

“ wiring. 

Pipes, Standard Threads on 

Placing Elect. Wires. 

Plant, Running Elect. 

Plunger, Deep Well. 

Pole, Positive. 

Polygonal nuts. 

Potential. 

“ service, Constant 

Pounding in engine. 

Pressure in stand pipe .... 

“ Initial. 

Safe boiler. 

“ Terminal. 

Priming. 

Pulley speed calculation .. 

Pump, Ammonia. 

“ Artesian. 

“ Capacity of. 

“ Deep well . 

“ Duplex v’lv.setting 

‘ ‘ Feed. 

“ governor. 

“ Lift of. 

“ testing. 

Quadrant. 

Rack, Reversing. 

Recipe, mending band saw 
“ Test’g iron and steel 

“ Tracing paper. 

“ Solder and fluid.... 

“ Steam cement. 

Refrigeration.. 

Apparatus. 190, 
“ Methods of... 


Refrigeration, Principle of. 181 
“ Testing ice 

machinery. 214 

Regulation of Feed. 57 

Repairs of Dynamo. 287 

“ Baud Saw. 108 

Resistance in Controller .. 302 

“ of metals. 310 

Rheostat.272, 308 

Rivets. 33 

Reversing rack. 331 

“ an engine. 100 

“ a motor. 308 

Rubber gloves, Use of ... 289 
“ belting, Cleaning. 248 
Reversing gear, Single ec¬ 
centric.330 

Rules and standard num¬ 
bers. 234 

Running electric plant.... 284 

Ruptures of boiler. 56 

Rusty steel, Cleaning. 247 

Safety fuse, Boiler.42, 68 

*• “ Electric ...303, 308 

“ pop valve. 62 

“ valve, Setting. 65 

“ “ Size of. 64 

Safe worki ng pressure.... 48 

Series wound. . .277, 308 

Shafting accidents. 245 

Shaft lining, Engine. 120 

Short circuit ... 312 

Shunt wound. 277' 

Slide valve. 96 

“ “ Balanced.133 

“ “ reversing. 100 

“ “ setting. 97 

Smoke.21, 53 

“ prevention. 25 

Sockets, Electric. 317 

Solder and fluid. 205 

Specific gravity... 13 

“ of ammonia 213 

Square root. 239 

Stacker, Hay. 334 

“ gearing. 332 

Standard babbitts. 335 

multipliers. 235 

numbers. 234 

“ threads on pipes 39 

Stationary motor.297, 308 

Stays, bolts, calculation ...37, 38 

Steam. 16 

“ Cleaning by. 247 

“ expansion . 18 


298 

308 

63 

252 

235 

13 

19 

233 

291 

277 

98 

13 

19 

19 

160 

277 

315 

39 

315 

284 

87 

252 

233 

251 

278 

119 

14 

102 

176 

102 

51 

239 

197 

84 

74 

87 

75 

73 

85 

81 

79 

273 

331 

168 

128 

274 

205 

222 

180 

, 197 

185 
















































































INDEX 


9 


Steam fitting... 246 

“ gauge . 89 

“ “ test. 65 

“ heating. 52 

*• High, low. 17 

“ pipes, Cement for... 222 

“ pressure and temp. 17 

“ Superheated. 17 

“ velocity. 18 

Steel and iron.61, 128 

Striking points . 122 

Substance, Three forms of. 11 

Surface car, Elect. 300 

Synchronizing. 278 

Table, Ammonia percent.. 213 
“ “ boil, p’nts 210 

4 4 Areas of circles. 235 

“ Boiler H. P. 153 

“ Brine solutions. 195 

“ Cold storage. 206 

41 C o n d u cti vity of 

metals. 310 

44 Engine H. P. 149 

“ Flame temperature. 2J 

44 Grate space. 20 

“ Heat’g surface H.P. 148 
“ Indicator springs... 154 

“ Polygonal nuts. 233 

4 4 Rivet sizes. 35 

44 Steam pressure. 17 

“ “ velocity. 18 

“ Standard babbitts .. 335 
44 Standard threads... 39 

44 Traction engineH.P. 328 

Tensile strength. 60 

Testing ammonia. 211 

4 4 boilers. 56 

“ circuit . 284 

“ ice machinery. 214 

*• insulation. 281 

44 iron and steel. 128 

“ pump. 79 

“ steam gauge. 65 

“ water.15, 195 

Thermal unit. 23 

Thermometers.175, 244 

Third rail system. 300 

Threads of pipe. Standard. 39 
Tracing paper, Recipe for. 274 


Traction engine. 324 

44 “ H. P. 328 

Transformer.272, 293 

Travel of crankpin and 

crosshead. 169 

Turning a ball. 229 

Twist drill grinding.231 

Unit, Electrical. 266 

44 Thermal. 23 

Vacuum, Ammonia pump. 216 
“ Water pump. .81, 115 

Valve, Bevel of. 66 

44 Bye pass../..207 

“ Check. 81 

“ Corliss. 135 

Duplex, To set. 75 

Gate. 82 

“ Link motion. 144 

“ rod, Length of..... 97 

44 rod adjusting, Cor¬ 
liss.139 

“ Safety. 62 

“ Slide. 96 

“ Slide, Balanced.... 133 

Ventilator. 242 

Vibration, Anvil.246 

Volt. 292 

Water.. .. 11 

“ Boiling points of. . 16 

44 column.. 42 

“ Composition of..... 12 

44 expansion .. 12 

44 Freezing. 180 

Purifying. 12 

‘ • measurements. 15 

“ as a solvent. 12 

44 tests.15, 195 

Watt.290 

Weights and measures.... 236 

Wire, Placing.315 

44 Size of. . 313 

Wiring, Electric. 309 

Yoke and Quadrant.273 

Zero, Absolute. 174 





































































ICE MANUFACTURING PLANT. 



CORLISS CROSS COMPOUND ENGINE 




























































Stevens’ Mechanical Catechism 


WATER 

Life, as it exists on our earth, depends on water 
and heat. Water is the most important sub¬ 
stance in nature. 

Question. —How does life depend on water? 

Answer. —Water is present everywhere, in the 
air, in the ground, in wood and even the hardest 
stone. About seven-eighths of the human body 
is water. Without water everything would be dry 
and lifeless. 

Q.—What are the most important qualities of 
water? 

A.—First, its abundance and universal presence; 
second, its quality of assuming easily either of the 
three forms of substance, solid , liquid and 
gaseous. Many substances can be in these three 
forms, but water changes from either one of them 
to the others within a very narrow range of tem¬ 
perature. It freezes solid (ice) at 32 0 F. (=o° C.) 
and turns to gas (vapor) at any temperature, most 
rapidly at the boiling point (212 0 F. or ioo° C.) 



12 QUESTIONS AND ANSWERS 

Q.—Is water an element or a compound? 

A.—A compound, composed of two gases, 
hydrogen and oxygen, in the proportion of one 
volume of oxygen to two volumes of hydrogen, or 
in weight one part of hydrogen to eight parts of 
oxygen. 

Q.—Can water be condensed by pressure? 

A.—Very slightly. Under a pressure of one 
atmosphere it may be compressed only about one 
twenty-thousandth of its bulk. 

Q.—Has water any solvent power? 

A.—Yes, it is the most universal and powerful 
solvent of all liquids. For this reason it is rarely 
found entirely pure. 

Q.—How can water be entirely purified? 

A.—By changing it to steam and condensing 
this. 

Q.—What taste or color has pure water? 

A.—Pure water is tasteless, odorless, colorless 
and transparent. 

Q.—Does water expand or contract when 
freezing? 

A.—It expands about 1-12 of its bulk. 

Q.—When has water the smallest bulk? 

A.—At the temperature of 39. i° F. (=4° C.) 

Q.—Would you call the expansion of water in 
freezing a force? 

A.—Yes. It exerts the tremendous power of 
30,000 lbs. per sq. inch. 


WATER 


13 


Q.—What is specific gravity ? 

A.—Density as compared with water. 92 lbs. 
of ice equal 100 lbs. of water at 6o° F. in volume. 

Q.—State the average impurities of saline matter 
in the Atlantic Ocean and in the Dead Sea? 

A.—The saline matter in the Atlantic Ocean 
amounts to 2,139 grains per gallon, and in the 
Dead Sea it reaches 19,736 grains per gallon. 

Q.—What is the proportion in area of land and 
water on the globe? 

A.—About 52 millions sq. miles are land, and 
about 196 millions sq. miles are water. 

Q.—Where do the clouds come from? 

A.—They are formed by the constant evapora¬ 
tion from the immense water surfaces of the globe. 

Q.—Is air an element or a compound? 

A.—Like water, it is a compound, composed of 
20.96 per cent oxygen, 79.00 nitrogen and 0.04 per 
cent carbonic acid. 

Q.—Which of these gases is the life-sustaining 
element? 

A.—It is the oxygen. This is the substance 
whose chemical union with combustibles we call 
combustion, whether in our lungs or in a fire-box. 

Q .—What is the difference in weight between 
air and water? 

A.—Air is 813.67 times lighter than water. 

Q.—Can it be proved that air has weight? 

A.—Yes, by comparing the weight of a large 


14 


QUESTIONS AND ANSWERS 


hollow globe when filled with air, with its weight 
after the air has been exhausted by an air pump. 

Q.—How much weight has the atmosphere per 
sq. inch? 

A.—The mean pressure of the atmosphere is 
stated at 14.7 lbs. per sq. inch. 

Q.—How is it that this weight does not crush us? 

A.—The pressure is exerted in all directions, 
and permeates the whole body. 

Q.—What is the meaning of such terms, as two 
or three “atmospheres”? 

A.—An atmosphere in this sense is the stand¬ 
ard or unit of air pressure, equal to the average 
atmospheric pressure at sea level (=14.7 lbs. per 
sq. inch). 

Q.—Is the atmospheric pressure not always the 
same? 

A.—No. The barometer shows the variations. 

Q.—What is the principle of the barometer? 

A.—The mercury in the closed vacuum tube is 
raised about 29.9 inches by the atmospheric pres¬ 
sure entering through the open tube. 

Q. —How high will the atmospheric pressure 
raise water in a vacuum tube? 

A.—About 33.9 feet. 

Q. —What is the pressure in pounds per sq. inch 
in a column of water in a standpipe? 

A.—Multiply the height of the column in feet 
by .434. Engineers generally figure one-half of 


WATER 15 

one pound pressure per sq. inch for each foot 
elevation. 

Q.—What are the common measures of weight 
and contents for fresh water? 

A.—A gallon weighs 8 1-3 pounds and contains 
231 cubic in. A cubic foot weighs 62 1-2 pounds 
and contains 1,728 cubic in., or 7 1-2 gallons. 

Q.—What kind of water would you prefer to use 
in a boiler? 

A. —Rain or atmospheric water. 

Q.—Why do you prefer rain water? 

A. —Because it does not contain minerals which 
scale the boiler heavily. 

Q.—Is rain water considered pure? 

A.—Yes, but in their fall raindrops collect many 
solid particles of dust, both in the air and on the 
ground. On the other hand, spring water contains 
almost invariably mineral matter, which causes 
corrosion and slight deposit in the boiler. Rain 
water is almost entirely free from elements that 
cause incrustation. 

Q.—What tests are there for impure water? 

A.—Litmus paper dipped in vinegar does not 
return to its true color in water containing earthy 
matter or alkali. A solution of a little prussiate of 
potash will turn water containing iron blue. A 
few drops of a solution of* a little good soap in 
alcohol, if put in a vessel of water, will turn it quite 
milky if it is hard; soft water will remain clear. 


STEAM 


Many engineers have asked for an explanation 
of the term “Steam, ” which we have endeavored 
to give in the following questions and answers: 

Q.—What is “Steam”? 

A.—Steam is the gas from water produced by 
ebullition, which is generally known to take place 
at 213 0 F. The passage of any liquid into the 
gaseous state is called vaporization, and the term 
“evaporation” especially refers to the slow produc¬ 
tion of vapor at the free surface of a liquid. In 
boiling vaporization goes on not only on the sur¬ 
face, but in the liquid itself. 

Q.—Is the boiling point of water under all cir¬ 
cumstances at 212.S° F.? 

A.—No. On high mountains, where the atmos¬ 
pheric pressure is very low, water boils at a much 
lower temperature, so that cooking cannot be done 
except in air-tight vessels; and under high pres¬ 
sure, as in steam boilers, water begins to boil 
at a much higher temperature. 

Q.—State if the temperature of the boiling point 
of water increases the same as the steam pressure? 

A.—No. The following table will explain the 

different temperatures at different pressures: 

16 


STEAM 


17 


STEAM PRESSURES AND TEMPERATURES 


Pressure. Temp. 

10.192.4 

15.212.8 

20.228.5 

25.241.0 

30.251.6 

35.260.9 

40.269.1 

45.276.4 

50.283.2 

55.289.3 

60.295.6 

65.301-3 

70 .306.4 


Pressure. 

Temp 

75 . 

..311.0 

80. 

.- 315-8 

85 . 


90 . 

- 324-3 

95....... 


100. 

. 332.0 

120. 

- 345-8 

130. 

..352.1 

140. 

- 357-9 

150. 

-563.4 

160. 

,..368.7 

170. 

- 373-6 

180. 

- 378.4 


Q.—What is the difference between high and 
low pressure steam? 

A.—High pressure is steam over 15 lbs. ; low 
pressure is 15 lbs. or less. 

Q.—What is superheated steam? 

A.—Steam removed from the water boiler and 
brought to higher temperature in a separate vessel. 

Q.—Does water evaporate when the air above 
its surface is exhausted by an air-pump? 

A.—The temperature could be elevated to 275 0 
before vaporization takes place, and when it does, 
the action will not be like ordinary ebullition under 
pressure of the atmosphere, but will be instan¬ 
taneous (explosive). 

Q ,—What is the boiling point of a liquid? 



























l8 QUESTIONS AND ANSWERS 

A.—A liquid boils when the tension of its vapor 
and the pressure it supports are equal. 

Q.—Why is steam called “latent” heat? 

A.—Because heat was expended (became insen¬ 
sible) in making steam. 

Q.—State the amount of heat required to con¬ 
vert i lb. of water at atmospheric pressure into 
steam? 

A.—Scientifically, it takes the same amount of 
heat that is required to melt 13 lbs. of gold or 3 
lbs. of steel. 

Q.—Which has the more expansive force, water 
or alcohol? 

A.—Alcohol has more than double the expansive 
force of water of the same temperature. The 
steam of alcohol at 174 0 is equal to that of water 
at 212 0 . When proper means can be invented for 
saving the fluid from being lost it is supposed that 
alcohol can be employed with great advantage as 
the moving power of engines. 


This table shows the velocity (per second) at 
which steam escapes into the atmosphere at 
given lbs. of pressure above one atmosphere. 


PRESSURE IN 
LBS. 

VELOCITY IN 
FEET. 

PRESSURE IN 
LBS. 

VELOCITY IN 
FEET. 

I 

540 

50 

1736 

3 

814 

60 

1777 

5 

98 I 

70 

l 8 lO 

IO 

1232 

80 

1835 

30 

I 6 OI 

IOO 

1875 

40 

l68l 

120 

I 9 OO 












COMBUSTION AND FIRING 


Q.—What is meant by combustion? 

A. —It is a chemical combination of oxygen with 
combustible material of any kind, commonly 
called fire. 

Q.—State the comparative weight of oxygen to 
nitrogen? 

A.—It is 16 to 14. 

Q.—How much air is necessary to consume a 
given quantity of fuel? 

A.—There is a fixed proportion between the 
oxygen required and the fuel gas to be consumed. 

Q.—How can this be determined? 

A.—We know that oxygen is 1-5 the bulk of air. 
Five volumes of air are necessary to produce one 
of oxygen; therefore, as two volumes of oxygen 
for each of gas are necessary, it follows we must 
provide ten volumes of air. 

Q.—What is perfect combustion? 

A.—Combustion is perfect, when no gas is 
developed that does not instantly unite with 
oxygen. 

Q.—What amount of air is required to consume 
1 lb. of coal? 

A.—It requires 15 lbs. of air, on an average. 

19 


20 


QUESTIONS AND ANSWERS 


Q.—How many cubic feet in i lb. of air? 

A.—One lb. of air contains 13 9-107 cubic feet. 
Q.—Give the proper air spaces for different 
fuels? 

A.—The different sizes of air spaces between 
grate bars for different fuels are as follows: 


Schuylkill anthracite pea coal. M inch 

Lehigh anthracite pea coal. Y% “ 

“ “ chestnut. Y “ 

stove... % “ 

“ “ broken. Y “ 

Cumberland bituminous. Y “ 

Wood. Y to 1 “ 

Sawdust.3-16 to “ 


Q.—Of what color are flames in different 
temperatures? 

A.—They are as follows: 

Color. Temp. Color. Temp. 

Red, just visible.. 977 deg. Orange, deep.2010 deg. 

“ dull.1290 “ “ clear ....2190 “ 

“ cherry, dull.. 1470 “ White heat.2370 “ 

“ “ full..1560 “ “ bright 2550 “ 

“ “ clear.1830 “ “ dazzling.. .2730 “ 

Q.—State the successive stages of firing coal, 
and the temperatures, beginning with the match? 

A.—A slight friction of 150° ignites the phos¬ 
phorous ; when this reaches 500° the sulphur burns; 
next 8oo° ignites the wood or shavings, then i,ooo° 
ignites the coal gas. 

Q.—How is the philosophy of combustion 
known? 

A.—It is known through chemistry, 
















COMBUSTION AND FIRING 


21 


Q.-WVhat do you understand by coal? 

A.—Coal is a compound substance and may be 
decomposed by heat in several distinct elements. 

Q.—Which elements are of principal importance 
in the combustion of coal? 

A.—Two: carbon in form of coke, and hydro¬ 
gen, a gas. 

Q.—Are these all the heating properties in coal? 

A.—No, but the principal ones. 

Q.—Why does not coal commence to burn 
immediately when thrown upon the fire? 

A.—Because coal must first be heated and go 
through the process of decomposition. 

Q.—How does coal decompose in firing? 

A.—ioo lbs. of coal, when put in a fire, develops 
gases containing about 24 lbs. of hydro-carbon and 
free hydrogen, 9 lbs. of steam (water), 1.25 lbs. 
of sulphur and 1.2 lb. of nitrogen. While these 
are evaporated and consumed, the residuum, 
about 60 lbs. of fired carbon or coke, begins to 
burn, leaving finally about 4.55 lbs. of ashes 
(incombustible matter). 

Q .—What condition does smoke indicate? 

A.—It indicates poor combustion. 

Q.—Is it understood, then, that when there is 
no smoke there is perfect combustion? 

A.—No. The perfect combustion of coal in a 
furnace can only be effected by a large enough 
supply of oxygen. 


22 


QUESTIONS AND ANSWERS 


Q.—What is the object of a forced draught? 

A. —To increase the supply of oxygen. 

Q.—Does coke smoke while burning? 

A.—No. Smoke only comes from the gas dis¬ 
tilled from the coal. After the gas is distilled, that 
which is left is the coke. 

Q.—Where is the greatest heat when gas is 
being expelled from coal? 

A.—In the gas. 

Q.—Will the coke or solid coal burn while 
expelling gas? 

A.—No. A lump of coal may, however, be 
expelling gas in one place and burn in another 
where the gas has already been expelled. 

Q.—What is required to burn anything? 

A.—In order to burn anything it must be heated 
to a certain degree hnd kept up to that heat. 

Q.—How far does a flame enter a boiler tube 
of ordinary size? 

A.—The flame never enters more than a few 
inches. 

Q.—Then state what burns at the other end of 
the tube? 

A.—It is carbonic oxide. It has a low igniting 
temperature and takes fire after mixing with the 
atmosphere, making a blue flame attending the 
conversion of carbonic oxide into carbonic acid. 

Q.—The blue flame just spoken of—is it the 
same that entered the tube? 


COMBUSTION AND FIRING 23 

A.—No. The flame that entered the tube was 
extinguished, and any combustible matter still 
present went to waste. 

Q.—1. What is a thermal unit? 2. How many 
does a pound of coal yield? 

A.—1. It is the heat required to raise the tem¬ 
perature of 1 lb. of water i ° F. 2. 13,000. 

Q.—What becomes of the heat? 

A.—Fifty per cent is utilized, 40 per cent 
escapes up the chimney, and 10 per cent is lost by 
radiation. 

Q.—State the weight of 1 cubic foot of air? 

A.—A cubic foot of air weighs 535 grains. 

Q.—State the amount of air required for the 
combustion of 1 lb. of good free burning soft 
coal? 

A. —About 200 cubic feet. 

Q.—Is combustion always accompanied by 
flames? 

A.—No. Combustion is, chemically, a rapid 
oxidation, caused by the chemical union of oxygen 
with the combustible. The rotting of vegetable 
matter, the rusting of iron, the oxidation of brass 
are examples of combustion without flame. They 
cannot take place without air, which furnishes the 
oxygen. Combustion takes place in our lungs, 
which absorb the oxygen. Pure, fresh air con¬ 
tains oxygen in abundance. 

Q.—Where do we get the heat from? 


24 


QUESTIONS AND ANSWERS 


A.—The heat is produced by the chemical union 
of the air with the carbon and hydro-carbon of 
the fuel. We might as well expect to make steam 
without putting fuel on the grates as without sup¬ 
plying the fuel with the proper amount of oxygen 
as contained in air. 

> Q.—About how much air enters a furnace 
having a good natural draught? 

A.—About 530 cubic feet per minute to each 
square foot of grate surface. 

Q.—Suppose you had a 60 H. P. boiler with 25 
sq. feet of grate surface, allowing about 25 per 
cent of the grate surface for air space, how many 
square feet for air would there be, and how much 
would pass through the grates; also how many 
pounds of coal would be consumed per hour? 

A.—The air space would be 6^ sq. feet, the 
amount of air passed through would be about 
198,720 feet and the amount of coal about 1,000 lbs. 
per hour. In seven cases out of ten it will be 
found that the grates are choked with clinkers and 
the ash-pit filled with ashes, so that not more than 
25 per cent of stated amount of air could possibly 
reach the fuel. The fireman shovels in coal and 
wonders why he can’t raise the steam pressure, 
never dreaming that the required amount of air 
for the combustion of the amount of fuel thrown 
in could not possibly pass through the dampers, 
much less through the clogged grates. 


COMBUSTION AND FIRING 25 


Q.—Should the grate slope, and, if so, in which 
direction and how much? 

A.—It should slope inch per foot, from the 
front of the furnace to the bridge wall, down¬ 
ward. 


Q.—What fireman will best prevent the offen¬ 
sive and wasteful formation of smoke? 

A.—A fireman who keeps the grates free for the 
passage of air and always breaks up the coal into 
lumps about the size of a man’s fist and keeps it 
evenly distributed over the grates. 

Q.—Do you know of any practical 
and cheap device for the prevention 
of smoke? 

A.—A pipe inserted in the top of 
the stack, leaving an annular space 
of three inches between itself and the 
inside of the stack, and extending 
about eight feet down into the stack 
and projecting seven feet above it, 
is said to be an excellent and cheap 
device for preventing smoke and to 
save ten per cent of fuel besides. 

Q.—How does it work? 

A.—At starting the fire, thick smoke issues from 
the inserted pipe, while faint rays of smoke issue 
from the annular space. These almost immedi¬ 
ately disappear and from the central pipe only 
traces of smoke can be seen to issue. This proves 











26 


QUESTIONS AND ANSWERS 


that a cold circular draught descends around the 
hot upward draught, and reaching the combustion 
chamber hot and in abundance, improves the 
combustion. 

Q.—When should fresh coal be thrown in on the 
fire? 

A.—When the whole fire has reached a white 
heat, the door may be opened and a few shovelfuls 
of coal thrown on the front of the grates and the 
door closed as quickly as possible. 

Q.—What does this do? 

A.—The gases distilled from the fresh coal will 
be ignited while passing over the hot coals on the 
rear of the grates, and instead of giving off a dense 
black smoke the hydro-carbons will be entirely 
consumed. 

Q.—What should be done then? 

A.—When the coal has ignited it may be pushed 
back over the grates and a fresh supply thrown in 
front again. This kind of firing will prevent 
smoke, if anything will, but it is hard work for the 
fireman, and when such services are given they 
will be appreciated and encouraged by the 
employer. 

Q.—About how thick should fires be for different 
coals? 

A.—For anthracite coal the thickness should be 
about 8 inches, for soft coal about io inches and 
for coke about 12 inches. 


COMBUSTION AND FIRING 


27 


Q.—Suppose you could not carry a fire bed of 
the desired thickness without blowing off steam, 
what would you do? 

A.—I should reduce the grate surface area by 
laying in fire brick next to the bridge wall and 
next to the sides of the furnace to the height of 
8 or 10 inches. 

Q.—In starting a fresh fire under a cold boiler 
how would you proceed? 

A.—First, have two gauges of water in the 
boiler, then cover the grate bars all over with coal, 
leaving a space in front for some light wood and 
shavings; cover the back with some heavy wood 
on the coal, close the ash-pit doors tightly and 
partly close the furnace doors when the wood is lit. 
The coal on the grate prevents warping. 

Q.—Why not place the coal on top at the 
beginning? 

A.—Because it would prevent the free access of 
air to the wood. The air enters through the fur¬ 
nace doors and the draught carries the flames 
between and over the coal in the rear, gradually 
heating it and distilling the gases out of it, which 
ignite, adding to the heat. 

Q.—Then what should be done? 

A.—After wood is burning, coal should be 
thrown on, the furnace doors closed and pit doors 
opened. 

Q .—Is it a good idea to hurry a fire? 


28 QUESTIONS AND ANSWERS 

A.—No. It should be allowed to burn gradually 
by feeding the fire with a little coal at a time. 

Q.—Is it good policy to stir a fire often? 

A.—No. It should be left alone as much as 
possible. 

Q.—Why is it not good policy to stir a fire often? 

A. —Because it would have a tendency to drop 
all the small coal and fire through the grate. 

Q.—How is the draught controlled? 

A.—By the chimney damper and ash-pit doors. 

Q.—How often should a fire be cleaned, and 
when? 

A. —As often as necessary—when clinkers pre¬ 
vent the admission of air through the grates. 

Q.—Can it be seen by the color of a fire when 
it should be cleaned or is badly managed? 

A.—Yes. Dark spots, heavy smoke and blue 
flames are the best points to show it. 

Q. —How would you clean a fire? 

A.—Open one of the furnace doors, shove the 
live coals either back or to one side; then rake out 
the dead clinkers, throw in a little wood or coal and 
pull the live coals over; then throw on fresh coal. 

Q.—Would you use wet coal? 

A.—No. It produces soot and injures the fire 
sheets by corrosion and in other ways. 

Q.—How and when would you bank a fire? 

A.—First, clean the fire on one side of the fur¬ 
nace, throw on a few shovels of fine coal and cover 


COMBUSTION AND FIRING 


29 


it with wet ashes; tightly close the ash-pit and 
furnace doors, leaving the stack damper slightly 
open to let out the gas. A fire banked in this 
manner will keep all night. 

Q,—How many gauges of water would you con¬ 
sider safe with a banked fire? 

A.—Three full gauges. 

Q.—Is it a good idea to entirely close the 
chimney damper with fire on 1 the grates? 

A.—No. It is dangerous, as gas may collect in 
the flues and cause an explosion, which would ruin 
the boiler and burn the grate bars. 

Q.—Does a banked fire benefit a boiler? 

A.—Yes. It prevents any contraction owing to 
the difference in temperature. 


LOCOMOTIVE FIRING 

Q.—How would you fire a locomotive boiler on 
the road, run light on coal, avoid much smoke and 
have the boiler steam well? 

A.—Fire a little at a time and often, also keep 
the fire level as near as possible. Fire with even¬ 
sized coal and look out for clinkers in the box; 
also close door after each shovelful. 

Q.—What understanding have you of steam 
pressure as shown on the gauge? 

A.—It indicates the pressure on each square 
inch against the inside of the boiler. 


30 QUESTIONS AND ANSWERS 

Q.—Where would you place a safety plug in a 
boiler having a fire-box? 

A.—In the center of the crown sheet. 

Q.—Explain why steam is exhausted through 
the stack? 

A.—Without it the draught would be too weak 
for the needs of a locomotive. It forces the air 
out of the front end up the stack, creating a 
draught which causes the gases and products of 
combustion in the fire-box to fill the space; this in 
turn allows the pressure of the atmosphere to force 
fresh air up through the grates, making a steady 
and strong flow of air into the fire-box. 

Q.—Is enough air supplied through the grates to 
form perfect combustion? 

A.—Not under all circumstances. 

Q.—Are there other ways of admitting air into 
the fire-box? 

A.—Yes. Air is admitted over the fire through 
hollow stay-bolts, also air holes in the fire-box 
door and lining. 

Q.—Do the holes in the door answer any other 
purpose? 

A.—Yes. If drilled in line with the lining holes, 
the light from the fire will light up the deck and 
coal space. 

Q.—Does the cold air that is admitted over the 
fire mix with the gas and burn immediately upon 
entering the fire-box? 


COMBUSTION AND FIRING 31 

A.—No. It is heated first, then mixes with the 
gas and burns. 

Q.—State the object of the brick arch in the 
fire-box? 

A.—It is there to hold the gas expelled by the 
coal so it will mix with the air admitted. It 
heats the air and prevents the emission of dense 
black smoke. It protects the flues from the cold 
air that passes through the door when firing, and 
checks the exhaust’s effect upon the fire, so that 
small particles of coal chat would otherwise go 
through the flues and be lost, are kept in the fire 
to be burned. 

Q.—Is the brick arch a coal saver? 

A.—Yes. It saves coal by holding in the gas so 
it can burn, and prevents the flue sheets and flues 
from sudden cooling when the fire-box door is 
opened. An arch is a disadvantage if the side 
sheets are patched or leaking, as the arch makes 
them worse. It keeps them hot after the other 
parts of the fire-box are cool, consequently it 
causes expansion where there should be contraction. 

Q.—What effect does an open door have on the 
fire and flue sheet when an engine is working? 

A.—It lets the air in through the door instead of 
through the fire, which cools the flue sheet and 
lowers the pressure. When firing see that the 
door is closed after each scoop of coal. 

Q .—Why open and close the door so often? 


32 


QUESTIONS AND ANSWERS 


A.—It gives each previous shovelful a chance to 
ignite. 

Q.—Is the wetting of coal for locomotives any 
advantage over dry coal? 

A.—No, but with large lumps the water gets in 
the cracks and splits the lumps as soon as heated, 
and for small coal it helps to coke into a lump, so 
that it will stay in the box and burn instead of 
going out with the first exhaust. 

Q.—Of what use is a blower? 

A. —It is very useful. It makes a forced draught, 
which prevents black smoke, and keeps the smoke 
and fire in circulation when engine is shut off. 

Q.—How is smoke kept from trailing over the 
train when running shut off? 

A.—Sometimes partly opening the door will 
remedy the trouble, otherwise the blower must be 
turned on a little to force the draft. Good judg¬ 
ment should be used. 

Q.—Is it wasteful to have an engine frequently 
blow off at safety valve? 

A.—Yes; but if the pressure can be kept within 
5 lbs. of the blowing off point it will be easier on 
the boiler and will save water and coal. 

Q.—Give the proper size of a locomotive stack 
— inside diameter? 

A.—It should be 2)4 inches smaller in diameter 
than the cylinder of the engine, 


BOILERS 


Locomotive and Stationary 

Q.—State the different classes and styles of 
boilers in use? 

A.—There are three classes—marine, stationary 
and locomotive—and six styles—marine, locomo¬ 
tive, upright, flue, tubular and water tube boilers. 

Q.—How are the different classes fired? 

A.—The marine, upright and locomotive (hang¬ 
ing fire-box) are fired internally, but the stationary 
boilers are mostly fired externally. 

RIVETS 

Q.—Are boiler shells single or double riveted? 

A.—The end seams are all single riveted. The 
longitudinal seams are single riveted for low 
pressure and double for high pressure. 



Q.—Why are longitudinal seams double riveted 
and circular or end seams single riveted? 

A.—Because the strain is greater on the sides 
33 






34 


QUESTIONS AND ANSWERS 


than at the ends, as the steam pressure has more 
surface to work on. 





Q.—What is the distance generally between 
rivets of a single, or double riveted boiler shell? 

A.—Single rivets are generally 2^ inches, and 
double rivets 2^ inches apart. 

Q-—What should the diameter of rivets be for 
any size sheet to make up the maximum shearing 
strength? 

A.—The diameter should be equal to twice the 
thickness of plate to be riveted. 

Q.—What is the usual distance between the edge 
of rivet hole and edge of sheet? 

A.—The full thickness of rivet used. 

LAP JOINT RIVETING 

The following table indicates the various sizes, 
etc., of rivets for plates of different thickness: 






single riveted lap joint. 


DOUBLE RIVETED LAP JOINT. 













BOILERS 


35 


THICK- 

DIAM- 

DIAM- 




STRENGTH IN % 

NESS 

ETER 

ETER 


PITCH. 

OF SOLID. 

OK 

PLATE 

OF 

RIVET. 

OF 

HOLE. 






SINGLE. 

DOUBLE 

SINGLE. 

DOUBLE. 

i in. 

| in. 

U in. 

2 

in. 

2 s in* 

0.66 

0.77 

h “ 

n “ 

3 * i 

4 

2 TS 

t i 

‘ ‘ 

0.64 

O.76 

I “ 

3 << 

4 

H “ 

2£ 

< ( 

2f “ 

0.62 

0.75 

r 7 s 

13 “ 

I 6 

I 

2 *r 3 (8 

< i 

“ 

0.00 

0.74 

i *< 

7 «« 

g 

it “ 

2 * 

( < 

3 “ 

0.58 

0-73 


This table is applicable when steel rivets are 
used in steel plates, or iron rivets in iron plates. 
When iron rivets are used in steel plates, both 
rivets and rivet holes should be larger by 1-16 of 
an inch. 

SINGLE RIVETED BUTT JOINT. 

When plates thicker than y z inch are used, the 
joint should be a butt joint with double fish plate. 
(See cuts.) 

BRACES AND STAY BOLTS 

Q.—Where should braces be put in a fire-box 
boiler? 

A. —On the crown sheet, in water leg, in dome 
and on all flat surfaces. 

Q.—What kind of braces should be used? 

A. — In the dome, crowfoot or solid braces; on 
flat surfaces and between water sheets, stay-bolts; 
on the crown sheet, crown bars and stay-bolts; in 



DOUBLE RIVETED BUTT JOINT. 
























36 QUESTIONS AND ANSWERS 

the boiler shell crown radial braces; and in 
corners gussets. 



Q.—How is the load on a brace calculated? 

A.—Multiply the supported area by the steam 
pressure and divide the product by the number of 
braces. The quotient gives the strain on each 
brace. The law allows not more than 6,000 lbs. 
per sq. inch of cross section of brace. A round 
brace of 1 yi inch diameter has 1 sq. inch area in 
cross section. 

Q.—How can it be known whether a brace is 
really carrying the intended load? 

A.—If it does, it will give an even, clear sound 
when tapped with a hammer or the like. 

Q.—How are braces put in properly? 

A.—Have the brace about 1-16 of an inch short, 
heat it red hot in the center and put in place. It 
will shrink tight when it cools. 

Q.—Why is the flue sheet thicker than the boiler 
shell sheets? 

A. —Largely because it is weakened by the many 












BOILERS 


37 


flue holes cut in it, and it has to support the weight 
and sag of the flues. 

Q.—Give the number of square feet of heating 
surface allowed to a horse-power in different types 
of boilers? 

A.—For vertical 12 sq. feet, for horizontal 
tubular 15 sq. feet. 

Q.—How is a boiler’s horse-power determined? 

A.—Add together all the areas, in sq. feet, of 
heating surface up to the fire line (shell, tubes, 
back head); subtract from this sum the cross 
section area of all the tubes and the area of the 
front head less the tubes, and divide the remainder 
by 15 if horizontal, by 12 if vertical. See pages 
148 and 153. 

Q. —Give tonnage strain on the crown sheet of a 
fire-box? 

A.—Multiply the length by breadth inches, 
divide by 12 for feet, multiply answer by steam 
gauge pressure and divide by 2,000. 

STAY-BOLTS 

Q.—Explain the use of stay-bolts? 

A.—They are used to keep apart two plates, 
leaving a water space between. 

Q.—State the surface of plate a stay-bolt must 
support? 

A.—The support is represented by the area 
enclosed between four bolts. 


38 QUESTIONS AND ANSWERS 

Q.—How is the area between the four bolts 
found? 

A.—By multiplying one distance by the other. 
The answer will be each bolt’s support. 

Q.—What pressure do the four bolts have to 
withstand? 

A.—Multiply the area by highest boiler pressure. 
The product is the strain on cross sectional area. 

Q. —State the strain on a single stay-bolt? 

A.—It must not be over 6,000 lbs. per sq. inch 
cross sectional area. Rule: Multiply cross sec¬ 
tional area of bolt by 6,000, divide by steam 
pressure and extract square root of quotient. (See 
under Miscellaneous, page 239.) 

Q.—In examining the inside of the boiler, what 
are some of the defects for which you would be on 
the lookout? 

A.—For missing pins from the braces, slack 
braces, leaky socket bolts, defective riveting, 
defective heads to the rivets and for broken or 
loose stays. 


Q.—Name some appliances necessary about a 
steam plant? 

A.—A boiler and fittings, a pump or injector, 
piping for the feed water apparatus, steam pipes, 
globe valves, feed valves, feed water heater, steam 
trap, chimney and dampers, safety valve, check 
valve, the fire front containing the fire and pit, 



BOILERS 


39 


also flue doors, grate bars, and bearing bars, dead 
plates, man and hand hole plates, thimbles, water 
gauge cocks and glass gauge, blow-out cock, 
fusible plugs, steam gauge, fire tools, flue brush, 
gaskets and scaling tools, also hose for washing 
out the boiler, shovel, slice bar, rake, hoe, etc. 


STEAM FITTINGS 



Return Bend. Return Bend. 


Flange Union. Close Pattern. Open Pattern. 

Pipes of bore have 27 threads to the inch; 
pipes of X or X" have 18 ; pipes of X or have 
14; pipes of from 1 to 2" have ; larger ones, 8. 



Close Nipple. Long Nipple. 

(SipTlng. 



Q._Name the principal features of the brick¬ 
work about a horizontal boiler? 


40 


QUESTIONS AND ANSWERS 



Globe Valve 


A.—Binder bars, back stays, cleaning out doors, 
iron rollers and plates for the boiler lugs to rest on. 

Q.—What is a globe valve? 

A.—It is a valve in a round 
or globe chamber, used on 
boilers, engines, etc. 

Q.—What are thimbles on 
boilers? 

A.—They are heavy castings 
riveted oh the upper shell of 
the boiler with planed flanges 
to which are bolted the safety 
valve and main steam pipe. 

Q.—Is a horizontal boiler placed level on its 
saddles? 

A.—No, it is given a slight tilt (i% inch) toward 
the back, so all the water can be drained out 
through the blow-off. This also insures having 
always water at the end opposite the gauge cock. 

Q.—How are the sizes found of steam, water 
and gas pipes? 

A.—By measuring their inside diameters. 

Q .—How do you find the size of a boiler tube, 
flue or gauge glass? 

A.—By the outside diameter. 

Q.—In taking charge of a new plant, what is 
the first thing to do? 

A.—Look after the water and steam pipes, also 
the valves connected with them. 



BOILERS 


41 


Q.—Does water become lighter or heavier in a 
boiler under steam pressure? 

A.—It becomes lighter per cubic foot as its 
temperature increases. 

Q.—State as near as practicable the place to tap 
an upright boiler for the lower gauge cock? 

A.—Two thirds the distance between the two 
flue sheets, measuring from the bottom flue sheet. 

Q.—Where would you place the lower gauge 
cock in a submerged tube vertical boiler? 

A.—From to 4 inches above the top flue 
sheet, according to the size of the boiler, so that 
the top ends of the tubes would always be 
submerged. 

Q,—Where is the water line of a horizontal 
tubular boiler? 

A.—From one and a half to two inches above 
the flues. 

Q.—Where is the fire line? 

A.—On outside of shell and in line with the 
upper row of flues. 

Q.—Where is the lower gauge cock in a hori¬ 
zontal tubular boiler? 

A.—An inch and a half to two inches above the 
upper row of flues. 

Q.—Where is the water pipe tapped in a boiler 
head for a water-combination column? Where 
is the steam pipe tapped, and what size of pipe is 
used for making the two connections? 


42 


QUESTIONS AND ANSWERS 


TOP OF UPPER 
ROW OF FLUES 


TO WATER SPACE 
OF BOILER 8ETWEf 
THE TWO UPPER 
Of FLUES ANO SHELL 


A.—The water pipe 
is generally tapped 
centrally between the 
two upper rows of 
flues and the shell of 
boiler. The steam 
pipe is tapped in the 
top of the shell or in 
the dome. The con¬ 
necting pipes should 
not be smaller than 
1 14 inch diameter. 

Q. — How often 
would you blow out 
the gauge glass during 
the day? 

A. — About four 
times, or as often as 
necessary. 

Q.—Is a glass gauge always perfectly reliable? 
A.—No. The gauge cocks must be tried even if 
a glass gauge is used. 

Q.—Where is the safety plug usually placed in 
a water tube or flue boiler? 

A.—In water tube boilers they are generally 
placed four inches above the bottom of the drum, 
and not in the tubes. In flue boilers it is some¬ 
times screwed in the top of one of the upper flues, 
but of late it is the custom to tap the crown of the 

























BOILERS 


43 


shell about 15 inches 
back of the dome and 
there insert a half-inch 
pipe, reaching to within 
^ of an inch of the flue 
line. The top of this 
pipe is tapped into a 
brass chamber, in the 
top of which the safety fuse plug is screwed in. 

Q.—How does this arrangement work? 

A.—When the water in the boiler falls below the 
lower end of the safety plug pipe (indicated by a 
dotted line in the cut), the dry steam enters it, 
passes into the chamber and fuses the plug, the 
steam escapes and gives warning. See also page 68. 

Q.—At what temperature does the plug fuse, 
and what is it made of? 

A.—It is made of Banca tin which fuses at 
420° F. 

Q.—What causes channeling and grooving in a 
boiler? 

A.—They are caused by the mechanical action 
produced by unequal expansions and contractions. 

q. —Where would you feed water into a boiler 
to prevent grooving, etc.? 

A.—Feed near the water level of the boiler 
instead of near the bottom. 

Q .—Which is the best arrangement of the feed 
pipe? 







44 


QUESTIONS AND ANSWERS 


A.—It should enter the front head just above 
the tubes and a few inches away from the shell. 
It should then extend back to within a foot or so 
of the back head, then cross over and discharge on 
the opposite side, downward, between the tubes 
and shell. In this way the feed water becomes 
well heated before discharging into the boiler. 

Q.—How large should a feed pipe be? 

A.—According to the .size of the boiler, from i 
to \ ]/ 2 inches. 

Q.—How large should the blow-off pipe be? 

A.—Ordinarily 2 to 2]/ z inches diameter. 

Q. —Where should the blow-off pipe be attached 
to the boiler? 

A.—Underneath its back end. The shell should 
be re-enforced with a flange riveted on, and the 
pipe should be protected from the action of the 
flames and hot gases from the furnace by a fire 
brick stand. 

Q.—Why is malleable iron used for the elbows 
in the fire? 

A.—Cast iron ones would burn or break. 

Q.—Is it dangerous to empty a boiler when the 
tubes or flues are hot? 

A.—Yes; and it is also dangerous to hastily fire 
up a boiler, because where the draught and com¬ 
bustion are sufficient for a white heat, the plates, 
no matter how good they may be, cannot with 
certainty resist the terrible heat. 


BOILERS 


45 


Q.—State causes of defective circulation. 

A.—It is caused by flues being too close together, 
scale thickening on them, and flues set zigzag. 

Q.—What construction of a boiler would be con¬ 
sidered successful and economical? 

A.—For a tubular boiler place the flues in 
vertical rows, leaving out the center row; good 
circulation is when water goes down in the center 
and rises at the sides where the heat strikes it. 



Q.—How much steam-space is there in a boiler? 

A.—About X °f the internal capacity. (In the 
cut the water surface is indicated by dotted lines, 
and the height of the steam space by b.) 

Q.—Give the space between the flues of a well- 
made boiler? 

A.—The proper .space should be half the 
diameter of the flue. (See the cut above.) 

Q.—What amount of water in weight can be 
evaporated by one pound of good coal? 




4 6 


QUESTIONS AND ANSWERS 


A.—The average is from six to ten pounds. 

Q.—What waste of heat is there if 1-16 inch of 
scale is in the boiler? 

A.—Some of the best authorities claim from io 
to 15 per cent of fuel, and in this proportion 
upward according to thickness of scale. 

BOILER EXPLOSIONS 

Q.—What causes a boiler to explode? 

A.—It may be one or several of various causes. 
Defects in material or construction, or improper 
management account for most explosions. 

Q.—What is the scientific explanation of an 
explosion? 

A.—A boiler explodes when the pressure within 
exceeds its resisting power. 

Q.—What decides a boiler’s resistance? 

A.—The strength of its weakest spo£. It is 
there that an excessive pressure breaks through 
first. 

Q.—Why are the parts surrounding the weakest 
spot affected? 

A.—The break decreases their resisting power, 
while the shock and the sudden increase in the 
generation of steam manifold the pressure. 

Q.—Does all the water instantly change to 
steam? 

A.—No, but with a speed increasing at such a 
rapid rats that jt seems instantaneous, 



BOILERS 


47 


Q .—Is low water often a cause of explosion? 

A.—Yes, when the engineer tries to fill the 
boiler quickly, instead of very slowly. If a large 
amount of c'old water suddenly enters a hot boiler 
with a high pressure, too much of it changes to 
steam, at once raising the pressure beyond the 
resistance of the boiler. 

Q.—Is it proper, then, to feed water into a 
boiler when the water is out of sight? 

A .—Under no circumstances. 

Q.—What would you do? 

A.—I should immediately draw the fire, if a 
light one; if a heavy one, I should cover it over 
with wet ashes to deaden the heat. 

Q.—Why not draw out a heavy fire? 

A.—Because it would make more heat b} r 
raking. 

Q .—What would you do if the water was too 
high in the boiler? 

A.—Carefully open the blow-off and let out one 
gauge of water. 

Q.—What injury and danger are caused by 
heavy scale in a boiler? 

A.—The heat from the boiler plates is not com¬ 
municated to the water directly, but through the 
incrustation, a bad conductor. This necessitates 
an overheating of the plates, which deteriorates 
and weakens them rapidly. 

Q.—What is a bagged or blistered boiler? 


48 QUESTIONS AND ANSWERS 

A.—A bag is a bulging out of the plate; a blister 
is a bulging out not of the whole plate, but of 
the outer layer split from the inner. These 
defects are caused by too much sediment or scale. 
They weaken the boiler very much. 

Q. —How are these defects remedied? 

A.—By cutting the bagged or blistered piece 
out, and riveting a hard patch on the inside of the 
boiler. 

Q.—Why on the inside? 

A.—Because if put on the outside, the hole 
would form a pocket for sediment. 

Q.—How would you find the safe working pres¬ 
sure of a boiler? 

A.—Multiply twice the thickness of shell by the 
T. S. stamped on boiler plate and divide answer 
by 6 times diameter of shell in inches. If double 
riveted multiply by .70; if single, by .56. (Ans. 
in lbs. of pressure gives the safe load, at which the 
safety valve is set.) 

Q.—How is the safe working pressure found in 
cylindrical boilers? 

A.—Multiply one-sixth of the lowest tensile 
strength by the shell’s thickness (expressed in parts 
of an inch) at the thinnest part, and divide the 
product by the inside radius (half diameter) in 
inches. The answer will be the pressure allowable 
per square inch of surface for single riveted; if 
double riveted add 20 per cent. 


BOILERS 49 

Q —Which do you consider the safer, drilled or 
punched holes in boilers, for rivets, etc.? 

A.—Drilled holes. 

Q.—What are the first steps in economical boiler 
practice? 

A.—Keep the boiler perfectly clean; second, see 
that all rivets, seams, braces and connections are 
tight. 

Q .—Describe a good way of keeping a boiler 
clean? 

A. —Every boiler should be supplied with a sur¬ 
face blow-off, as a large percentage of the foreign 
matter held in suspension in water rises at the 
boiling point and can then be blown off before it 
has had time to deposit on the surface and flues. If 
not blown off, the heavier particles will be attached 
to each other until they become sufficiently heavy 
to fall to the bottom, when they will be deposited 
in the form of scale, covering the whole internal 
surface of the boiler below the water line. 

Q.—Where is the surface blow-off tapped? 

A.—It is tapped in the crown of the boiler 
and its pipe is bent so as to lie even with the 
average water level. When the valve is opened, 
the outrushing steam carries the surface water 
and any light matter floating on it along into the 
catch basin. This device is usually called the 
skimmer. 

Q.—When is the proper time and how would 


5 ° 


QUESTIONS AND ANSWERS 


you blow out a boiler for cleaning 
purposes? 

A. — Allow the furnace and 
boiler to cool down, open 
blow-off so the water and 
mud will escape, 
then wash out with 
a hose. Scrape the 
flues if possible, 
pull out all the Straightway Blow-off Valve 
sediment and scale left on the bottom of the 
shell with a long-handled hoe through the hand 
hole of the boiler and thoroughly rinse with water. 

Q.—Suppose a boiler was found badly corroded 
and pitted internally along the water line, and 
covered with a heavy deposit of sediment, baked 
on hard, what should be done? 

A.—Get inside the boiler and thoroughly scrape 
the shell, getting down to the sound plate, then 
with a stiff wire brush thoroughly oil or paint the 
corroded portion with red lead and boiled linseed 
oil, three coats. 

Q.—What are the causes of “foaming”? 

A.—Foaming comes from various causes, such as 
the mixing of water with steam, high water, 
irregular firing or feeding, impure or greasy water, 
too small steam space, dirty boiler, changing of 
water, etc. 

Q.—How is it known when a boiler foams? 



BOILERS 


51 


A.—It can be seen in the gauge glass by the 
water suddenly moving up and down, or by the 
sputtering at the gauge cock. 

Q.—Can foaming be overcome? 

A.—Yes, by partly closing large valves, opening 
fire doors and feeding water into boiler. 

Q.—What is meant by a boiler’s “priming”? 

A.—Entrance of water together with steam into 
the steam pipe, caused by high water, narrow 
steam pipe and sudden opening of valve. 

Q.—How would you remedy it? 

A.—By opening the valve slowly, or lowering 
water in the boiler. 

Q.—How would you gasket a steam joint so the 
gasket can always be taken out and replaced with¬ 
out injuring it? 

A.—By rubbing a little graphite and oil between 
the face of the flanges and the gasket, both sides. 

Q.—How would you remove a man or hand hole 
plate from a boiler? 

A.—Simply loosen nut, remove brace (dog or 
crab), and turn the plate to narrow side and take 
out. 

Q.—Why is a hand or man hole plate made 
oval instead of a true circle? 

A.—So they can be taken out and put in and 
new gaskets put on. 

Q.—When you have a battery of two boilers or 
more and one boiler has 80 lbs. steam pressure and 


5 2 


QUESTIONS AND ANSWERS 


the rest are cold, how would you proceed to con¬ 
nect them together? 

A.—Simply fire up the cold boiler and raise 
steam pressure to equal the one to which you 
wish to connect it. Never under any circumstances 
turn high into low pressure or hot into cold, 
because the sudden expansion may cause a serious 
rupture and may cost you your life. 

Q.—What is the first thing you would do on 
entering the boiler room in the morning? 

A.—See how much water is in the boiler by try¬ 
ing the gauge cocks, etc. 

Q.—Then what would you do? 

A. —Start a fire if I had one or two gauges of 
water. 


STEAM HEATING 

Q.—How would you open a steam valve to 
supply steam to a building for heating in the 
morning? 

A.—Open the valve slightly and wait until the 
pipe stops pounding, then gradually open a little 
more; it saves joints, gaskets, pipes, etc. When 
opening valves, make sure that the valve at the 
end of the return pipe is open until hot, then close 
it. 

Q.—How is the amount of pipe required for 
properly heating a room calculated? 

A.—By the following rules: 


BOILERS 


53 


One cub. foot of boiler to every 1,500 cub. feet of 
space. One H. P. of boiler to 40,000 cub. feet of 
space. One superficial foot of steam pipe to six 
superficial feet of glass in windows. One super¬ 
ficial foot of steam pipe to 100 sq. feet of wall, ceil¬ 
ing or roof. One sq. foot of steam pipe to 80 cub. 
feet of space. 

Q.—How do you find the heating surface of a 
radiator? 

A.—Multiply the total length of all the pipes by 
the outside circumference in inches, and divide by 
144. The answers give the square feet. 

Q.—Which is the best way to thaw out frozen 
steam pipes? 

A.—By laying some old cloth or waste on the 
pipe and pouring on boiling water, the pipe can be 
thawed out in 10 minutes. 

SMOKE AND CHIMNEY 

Q.—Would it be proper to have the chimney 
rough inside? 

A.—No; it should be as smooth as can possibly 
be made, and the area a little larger toward the 
top than at the bottom (inside). 

Q. —How much larger should the space be where 
the smoke or gases return through the flues 
than the grate surface? 

A.—It should be one-fifth larger in area than 
the grate surface. 


QUESTIONS AND ANSWERS 


54 . 

Q.—Where would you consider the proper place 
to close in against the sides of an externally fired 
boiler with brick (fire line)? 

A.—About in line with the center of upper row 
of flues all along the full length outside of boiler. 



SIDE VIEW 


This cut shows the proper way of enclosing a 
boiler in brickwork. The figures give the dis¬ 
tances in inches. 

Q.—Where does the greatest effect of the fire on 
the bottom of an externally fired horizontal boiler 
take place? 

A.—Just back of the bridge wall. 

Q. — From where is the height of a chimney 
measured? 

A.—From the top of the grate. 

Q.—What makes a chimney draw? 








































BOILERS 


55 


A.—The difference between the weight of the 
column of heated gases within and an equal column 
of cooler air without. 

Q.—Upon what does the draught capacity of a 
chimney depend? 



END VIEW 

A.—Upon its height, cross section area, and upon 
the temperature. 

Q.—State the size of chimney necessary to fully 
relieve the tubes or flues of a boiler or boilers of 
smoke, and give height? 

A.—The chimney should be one-fifth larger in 
area than all the tubes or flues combined, as the 
gas expands while passing through the chimney. 
The top should project io feet above the highest 
roof in the neighborhood to have a good draught 
and prevent smoking in boiler room. 








































56 


QUESTIONS AND ANSWERS 


BOILER TESTING 

Q.—Is the hydraulic test or the hammer test 
better? and why? 

A.—The hammer test is always reliable because 
a flawless metal gives a clear sound, and every 
part, inside and out, is examined by itself. In the 
hydraulic test a boiler may get strained, and when 
heated afterward, the expansion may bring out a 
leak. Government and insurance inspectors 
employ the hammer test. 

Q.—How do you find a broken or loose stay or 
rivet? 

A. —By holding a hammer against one side and 
striking the other side with another hammer. Any 
looseness can be discovered in this way by the 
feeling. 

Q.—If tested by the hydraulic test how much 
pressure is sufficient to test the boiler so as to 
carry a certain amount of steam pressure? 

A.—The hydraulic pressure test should be one- 
half more than the steam pressure to be carried, 
viz.: If steam pressure is to be 80 lbs. the hydraulic 
test should be 120 lbs. 


Q.—What is it that ruptures a boiler? 

A.—Unequal expansion or contraction. 

Q.—How may this be avoided? 

A.—To avoid this trouble it is necessary to 



BOILERS 


57 

exercise great care in raising steam. The fire 
should be increased gradually and the boiler have 
at least four inches of water above the top row of 
flues so the temperature may be gradually raised. 

Q.—Is it injurious to a boiler to open the fire 
doors often and suddenly cool the fire and sheets? 

A.—Yes; it is very unsafe. 

FEED .REGULATION 

Q.—Suppose you bad a battery of three boilers 
and the only valves near the boilers on the feed 
pipe were check valves, how would you feed the 
boilers evenly without using globe valves between 
the checks and boilers? 

A.—First, fire the boilers evenly; second, keep 
the pumps running steady, and if one boiler should 
happen to receive more water than the others use 
the blow-off valve of that particular boiler and 
regulate the height by it. 

Q.—Can uneven feeding be prevented? 

A.—Yes, by partially closing the stop valves of 
the boiler or boilers with high water, and, if 
necessary, by opening the stop valves of the low 
water boilers a little more. 

BOILER HORSE-POWER 

Q.—How can you find the amount of water evap¬ 
orated in a boiler? 

A.—Take the mean between the widths of the 


58 QUESTIONS AND ANSWERS 

two levels at the beginning and at the end of a 
space of 15 minutes, as indicated by the glass 
gauge. (See cut, pp. 42, 45.) Multiply the con¬ 
stant length of water surface with this mean width 
and multiply their product by 4. This gives 
the amount evaporated in cubic inches. Divid¬ 
ing the result by 1728, you get the answer in cubic 
feet. 

Example: If the glass gauge shows a difference 
of one inch, we measure across the face of the 
boiler half an inch above the last level. If this 
measures 48 inches and the boiler is 14 feet long 
(=168 in.), we have 48X168=8064. Multiplied by 
4=32,256 cub. in. per hour, or 18% cub. feet. 

Q.—Can you know from the amount of water 
evaporated in one hour, how many horse-powers 
have been developed? 

A.—Yes. 

Q.—How many cubic feet of water evaporated 
in one hour equals a horse-power? 

A. -One-half cubic foot, 3^ gallons or 864 cubic 
inches. 

Q.—Then, in our example, how many horse¬ 
powers were indicated? 

A.—Two times 18%, =37H. P. 

Q.—How can you find the horse-power of a 
tubular boiler by the heating surface? 

A.—First find the number of square inches of 
heating surface around boiler shell from fire line to 


BOILERS 


59 


fire line and in the flues; divide by 144 to get 
square feet; divide quotient by 15 if horizontal 
tubular, and by 12 if locomotive or vertical boiler 
to get H. P. 


FEED-WATER HEATER 

Q.—How many types of feed-water heaters are 
there? 

A.—Two. The open heater and the closed. 

Q.—What is the difference between them? 

A.—In an open heater the exhaust steam comes 
directly in contact with the feed-water, in a closed 
heater it does not. 

Q.—What is the object of a feed - water 
heater? 

A.—To save fuel by making use of the exhaust 
steam from the engine to heat the feed-water. 

Q.—At what temperature will a heater deliver 
water to a boiler? 

A.—That depends upon the type of heater and 
other conditions. A good heater of ample propor¬ 
tions should raise the temperature of the feed- 
water up to 200° F., or higher. 

Q.—What else is a heater good for besides heat¬ 
ing the feed-water? 

A.—It also purifies the water by extracting the 
scale-producing matter, and also the mud. 



6o 


QUESTIONS AND ANSWERS 


Q.— In using an open heater is there any danger 
of flooding the cylinder, and if so, how? 

A.—If there should be any stoppage of the out¬ 
flow of feed-water, it would flood the cylinder 
through the engine exhaust pipe, and perhaps 
cause a wreck. 


TENSILE STRENGTH 

4 

The tensile strength of metals is the load that 
would break a bar of one inch area in cross sec¬ 
tion if applied in the direction of its length. 

For a test of the tensile strength of iron or steel 
boiler plates, narrow strips are sheared from plates 
selected at random from a pile of them rolled at the 
same time—we will say the plates are steel and a 
quarter of an inch in thickness. These strips are 
at the middle reduced to a quarter of an inch each 
way (square). 

Suppose the testing machine pulls the first of 4 
strips asunder at 3,999 lbs. register, the second 
breaks at 4,001 lbs. and the last two at exactly 
4,000 lbs. each. Adding these all together we 
have the sum of 16,000 lbs., which, divided by 4, 
the number of strips tested, gives us 4,000 lbs. as 
the mean breaking strain of a quarter square 
inch of sectional area of steel. 

Multiply this by the number of quarter square 



BOILERS 


61 

inches in i square in. and we have the tensile 
strength in i square in. of section. There being 
16 quarter in. square in i square in. would give 16 
times 4,000, which equals 64,000 lbs. for a bar 
having 1 square in. of sectional area, which would 
be about the average tensile strength of first quality 
steel. 

After tensile strength is found, all the plates are 
stamped T. S. in that particular batch, and under¬ 
neath stamp 64,000. Sheets not stamped should 
not be rated at more than 48,000 lbs. T. S. 

STEEL AND IRON 

Q.—What is steel? 

A.—Steel is a variety of iron containing from 
one-half of one per cent to one and a half of one 
per cent of carbon. 

Q.—What is iron? 

A—Iron is a metal, the most abundant and the 
most important of all. It contains always 
impurities, such as magnesia, sulphur and 
phosphorus. It is hardly anywhere found native, 
but must be manufactured from ore. Cast iron is 
brittle and hard. Wrought iron , obtained by 
puddling , is softer and malleable. 

Q.—What are the principal advantages of steel 
over iron? 

A.—Greater elasticity and hardness, which by 
tempering may be increased to any desired degree. 


62 


QUESTIONS AND ANSWERS 


POP AND LEVER SAFETY VALVES 

Q.—Of what use are safety valves or pops? 

A.—They are to release the boiler automatically 
of all steam pressure above a certain point. 

Q.—Are there more than one kind of safety 
valves? 

A.—Yes—the old lever and the spiral spring 
safety valve. 

Q.—When steam is heard issuing from a safety 
valve, does it signify danger? 

A.—No; it is a signal of safety. It shows the 
valve is in working order and, if properly set and 
adjusted, it is a sure protection against trouble 

Q.—How do you set the safety pop valve? 

A.—Remove the cap H, and turn the set bolt O 
up for decreasing the pressure, or down for 
increasing it. (See cut.) 

Q.—How is the amount of reduction regulated? 

A.—Remove the set screw D (Fig. i) from the 
lower part of the case M, insert a pointed instru¬ 
ment in the screw hole, and with it turn down (to 
the left) the set ring, increasing the amount of 
loss, or up (to the right) for decreasing the amount. 
Then replace the set screw which holds the ring 
in position. 


SAFETY VALVE 


63 


V is the valve nut into 
which O is screwed. B is 
the valve. N is the upper 
cap over spring casing K 
inside casing M. S is the 
upper spring cap, R the 
lower. T is the testing 
lever, C the main casing, 

E the bolt bushing, F the 
bushing jam nut, A the 
guide for valve disc, J the 
guide for lower valve stem. 

Q.—How large a loss is it usual to have? 

A.—Three or four pounds. A valve can be set 
to lose less than half a pound in popping. 

Q.—What new device is there for deadening the 
sound of the pop valve? 

A.—The muffler attachment. (Fig. 2.) 

Q.—How is the Muffler Valve adjusted? 

A.—It can be adjusted on top without remov¬ 
ing from the dome. In order to adjust either the 
pressure or the blow-down, first remove the 
muffler I; this exposes the compression screw G, 
adjustable nut M, crosshead L, locking latch O, 
and check nut H. By loosening the check nut H 
and screwing down the compression screw G, you 
increase the pressure, and the reverse for lessening 
the pressure. (As a general rule from 1-16 to % 
turn will change the pressure of valve five lbs. 



Fig. 1 





6 4 


QUESTIONS AND ANSWERS 


either way.) By raising the locking latch O and 
screwing down on the adjusting nut M one notch 
you will reduce the blow-down one pound, and the 
reverse increases it one pound. 

A base. A 1 valve seat, B 
valve, C spindle, D spring, E 
follower, F F 1 main casting, 
F 2 thread hub, G compression 
screw, H check nut, I muffler, 
J the regulating ring, J J 1 
lugs on ring, K parallel rods, 
L cross-head, M adjusting 
nut, O locking latch. 

Q.—Give proper size of 
safety, valve for a boiler 
having 25 sq. feet of grate 
surface, allowing for 70 lbs. 
pressure? 

A.—For each foot of grate 
surface 22.5 feet boiler heating 
surface is allowed; 25X22.5=562.5. For the water 
in the boiler we allow 8.33 (the weight in lbs. of 
one gallon), which, added to the given pressure, 
gives 78.33. 562.5 divided by 78.33 equals 7.18 

sq. inches area, or a 3-inch diameter. 

Q.—How would you figure the pressure under 
a 3-inch safety valve with 75 lbs. boiler pressure? 

A.—Three times 3 equals 9 inches, times .7854 
equals 7.068 area, times 75 equals 530.1 lbs. 

Q.—What is the United States government rule 
about the relative areas of grate and safety valve? 










SAFETY VALVE 65 

A.—One square inch area of lever safety valve 
to 2 square feet of grate surface. 

Q.—State the general allowance among inspect¬ 
ors? 

A.—One inch area of safety pop valve to 3 
square feet of grate surface. 

Q.—Find area of a pop valve 3^ inches in 
diameter? (See table of areas, page 235.) 

A.—Multiply diameter by itself and then by 
decimal .7854; answer is the area, less decimals. 

Q.—When calculating the load on a safety valve, 
is allowance made for the atmospheric pressure on 
top of valve? 

A.—No; because it is present everywhere, inside 
and outside the boiler, and may be left out of the 
calculation entirely. 

Q.—Are the spring safety pops calculated when 
set? 

A.—No: as a rule they are set by a test steam 
gauge. 

Q.—What is done, if in such a test the needle 
does not show true at too lbs. pressure? 

A.—It is pulled off the pin, and then put back in 
the right position. 

Q.—What is meant by a strong or light needle? 

A.—It is termed strong when at the test it shows 
less than the true pressure, and it is called light 
when it shows more. 

Q .—What is it that keeps the face of the 


66 QUESTIONS AND ANSWERS 

valve and the seat in line (opposite) and causes 
the rise and fall to be even and true? 

A.—The valve spindle. 

Q.—What is the point of contact? 

A.—Where the valve and its seat meet. 

Q.—At what angle is the edge of the valve and 
its seat beveled? 

A.—At an angle of 45 degrees. 

Q.—How is it known when the safety valve is in 
good working order? 

A.—By the steam and gauge. Let the steam 
pressure rise enough to just move the safety—no 
more—and note the correspondence between the 
gauge and safety valve. 

Q.—Is there another way? 

A.—Yes—raising the valve by hand. 

Q.—How do you find the exact place where to 
place the ball (weight) on the long lever of the 
safety valve? 

A.—By applying the laws of leverage. (Page 241.) 

Q.—How do they apply in a safety valve? 

A.—The bar holding down the valve is a lever 
of the third kind, the pivot representing the 
fulcrum, the valve representing the power, and the 
ball representing the weight. (See cut, page 68.) 

Q.—Give the rule for calculating the distance 
from the fulcrum at which a given weight must be 
set to cause the valve to blow at any specified 
pressure. 


SAFETY VALVE 


67 


A.—1. Multiply the area of the valve in square 
inches by the pressure in pounds per square inch. 
Call this product “number i.” 

2. Multiply the weight of the lever in pounds 
by the distance in inches of its center of gravity 
from the fulcrum; divide the product by the 
distance in inches from the center of the valve to 
the fulcrum; add to the quotient the weight of the 
valve and spindle. Call this sum “number 2.” 

3. Divide the distance in inches from the center 
of valve to fulcrum by the weight of the ball in 
pounds, and call the quotient “number 3.” 

4. Subtract “number 2“ from “number i,” and 
multiply the difference by “number 3”; the prod¬ 
uct is the answer. 

Example: Given: diameter of valve 4 inches; 
distance from fulcrum to center of valve 4 inches; 
weight of lever 7 lbs.; distance from fulcrum to 
center of gravity of lever 15^ inches; weight of 
valve 3 lbs.; weight of ball 108.24 lbs. Blowing- 
off pressure 75 lbs. 

Area of 4" valves = 12.566 square inches 
75 X 12.566 = 942.45 


7 X 15.5 


—b 3 = 30.125 


4 -5- 108.24 = .0369 
942.45 — 30.125 = 912.325 
912.325 X .0369 = 35.66 inches. Ans. 

Q.— How do you find the pressure at which a 

safety valve will blow off when the weight and 

its position are known? 



68 


QUESTIONS AND ANSWERS 


A. — Divide the 
fulcrum into the 
length of lever, 
multiply by weight 
of ball, add weight 
of lever, valve and 
stem and divide by 

Iron Body Cross Safety Valve. Flange Ends. ^ va l vei 

Q.—How is the total weight of lever, valve and 
stem found? 

A.—The easiest way is to tie the stem with a 
string to the lever and attach a spring (scale) 
balance to the lever and valve, directly over the 
center of the valve, and weigh them in place. 

AUTOMATIC EXTINCTION OF FIRE BY STEAM AT LOW 
WATER 

In this device, recently patented in Vienna, a 
pipe reaches through the top of the boiler down to 
low water mark, so that steam will enter it as 
soon as the water falls below the mark. In the 
upper end of the pipe a safety fuse is melted by 
the steam, opening connection with a second 
pipe, which leads into the fire-box, where the 
steam extinguishes the fire. 

The fuse being a ring between a conical valve 
and its seat, the valve can be screwed down on 
the valve seat, as soon as the fuse is melted out, 
and a new fuse put in at any convenient time. 



INJECTORS 


69 


A whistle or bell is easily connected with the 
apparatus to give alarm. The air in the pipe first 
mentioned is exhausted through a stop-cock, 
after the boiler is heated. 


INJECTORS 

Q.—What is an injector and its use? 

A.—It is a substitute for a pump and is used in 
feeding a boiler with water. 

Q.—How is it that an injector forces water into 
a boiler against the pressure of the steam operating 
it? 

A.—The water and steam mingling at the com¬ 
bining tube, the steam jet is condensed, con¬ 
verted into a water jet. This water jet has a much 
smaller cross section area than the steam jet had, 
and as the energy of the steam jet is retained 
entire, a greatly increased velocity results. 

Q.—What forees the boiler check valve open? 

A.—The pressure of the water in the delivery 
pipe. 

Q.—State the velocity of steam passing through 
an inch pipe at 100 lbs. pressure? 

A. —Two thousand feet per second. 

Q.—Where would you look for trouble , if the 
injector stream broke and the same injector 
always before worked well? 




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70 























































































INJECTORS 


71 


A.—At the water and steam supply. 

Q.—Of what use is a steam nozzle? 

A.—It is for the actuating steam jets to pass. 

Q.—Where is the combining tube? 

A.—In the casing of the injector where the 
steam and water mix. 

Q.—Where is the delivery tube of an injector 
and what is its use? 

A.—It is where the maximum velocity of the 
stream is attained, and the jet overcomes the 
back pressure from the boiler. 

Q.—Are injectors divided into classes; if so, 
state how many? 

A.—Yes; they are divided into two general 
classes, the lifting and non-lifting. 

Q.—Can these two classes be subdivided? 

A.—Yes; they may be divided into six, namely, 
single tube, double tube, self-adjusting, restarting, 
open or closed overflow injectors. 

Q.—Is it a good idea to turn on more steam 
after overflow has been shut off? 

A.—No; it will cause the injector to break the 
stream. 

Q.—State some of the principal causes that 
make an injector’s stream break? 

A.—Not enough water supply, straws, chips, 
mud, cinders, leaky joints, overheated water, bad 
strainers, corrosion in the injector casing and low 
steam pressure. 


72 QUESTIONS AND ANSWERS 

Q.—What rules are used for determining 
the proper size of an injector for different 
boilers? 

Rule i. For Vertical Tubular Boilers—reduce 
all dimensions to inches and multiply the circum¬ 
ference of the fire box by its height above the 
grate; multiply the combined circumference of all 
the tubes by their length; next subtract from the 
area of the lower tube sheet, the area of all the 
tubes and add the remainder to the sum of the 
area of the tubes and shell and divide total by 
144, and the quotient will be the number of square 
feet of heating surface. 

Rule 2. For Horizontal Tubular Boilers—reduce 
all dimensions to inches and multiply two-thirds 
of the circumference of the shell by its length; 
multiply the length of the tubes by their combined 
circumference; next subtract from two-thirds of 
the area of both heads the combined area of the 
tubes and add the remainder to the sum of the 
tubes and shell, divide total by 144, etc. 

Rule 3. For Water Tube Boilers.—Proceed to 
find the area of all heating surfaces exposed to the 
radiation of gases from the furnace of boiler, and 
if area is in inches, divide by 144, etc., as above. 

After finding the heating surface, as per rule 
1, 2 or 3, divide by 30 (see page 150) to get the 
horse power, and allow 10 gallons of water per 
hour for each horse power. 


FEED PUMPS 


73 


Q.—What would be a short rule then? 

A.—If H. P. is known, multiply number by io 
to find number of gals, of water the injector should 
deliver per hour. If H. P. is not known, multi¬ 
ply number of sq. feet of heating surface by 3. 


FEED PUMPS 

Q.—Name the different kinds of pumps used 
daily for boiler feeding, etc. ? 

A.—Single action, with two valves, receiving 
and discharging; the double action, with two or 
more discharging valves. The latter receives and 
discharges water at both ends of water cylinder 
and has a steam cylinder attached to work the 
pump. The duplex is a combination of two 
double action pumps all cast together side by side. 

Q.—What are the relative proportions of steam 
and water cylinders of feed pumps? 

A. — The steam cylinder is 1-3 larger in diameter 
than the water cylinder. 

Q.—In setting up a steam pump, how is it 
leveled? 

A.—By leveling the discharge valve seat length¬ 
wise and crosswise. 

Q.—Give rule to find area of a steam piston in 
connection with a pump? 

A.—Multiply the area of water plunger by 2. 

Q .—Of what are pump valves made? 



74 


QUESTIONS AND ANSWERS 


A.—Hard or soft rubber, brass and sometimes 
vulcanized fiber and wood. 

Q.—Can you give a close rule to find the sizes 
of steam pipes for cylinders? 

A.—Divide the area of steam piston for steam 
pipe by 64. For exhaust divide the area by 32. 
For discharge pipe divide the area of plunger by 
3. For the suction divide area of plunger by 2. 

Q.—Suppose you had a duplex pump, size 8 in. 
water by 10 in. steam by 12 in. stroke and 3 in. 
diameter plunger rod, making 100 ft. piston travel 
per minute, how many gallons of water would 
the pump deliver, having full supply of water? 

A.—First find the area of plunger face—8 times 
Sin. equals 64, multiplied by .7854 equals 50.2656, 
by 12 in. stroke equals 603.1872, by 4 cylinder ends 
equals 2412.7488 cubic in. Now subtract the cubic 
contents of 3 in. diameter plunger rod 12 in. 
stroke in one end of each water cylinder from the 
total cubic inches and divide by 231, which gives 
gallons for one stroke, 4 ends. This multiplied 
by 100 piston travel gives total. Three multiplied 
by 3 equals 9, by .7854 equals 7.0686, by 12 equals 
85.032, by 2 equals 170.064, subtract from 2412.7488 
equals 2242.6840, divided by 231 cubic inches in a 
gallon equals 9.708 gals, one stroke, multiplied by 
100 equals 970.8 gals, per minute. This rule holds 
good on other pumps. 

Q.—Give quick rule to find quantity of water 


PEED PUMPS 75 

pumped in one minute, pump making ioo ft. of 
piston speed per minute? 

A.—Multiply the diameter of the water plunger 
by itself, then multiply the product by 4. Answer 
gives gallons for one pump; if for two pumps mul¬ 
tiply answer by 2 and so on. 

Q.—How could the horse-power be found 
necessary to pump water to a given height? 

A.—Multiply the total weight of water in pounds 
by the height in feet and divide by 16,500. This 
allows for water friction and steam loss. 

Q.—How are the steam valves of duplex pumps 
set and adjusted? 

A.—Remove the valve chest cover, place the 
rocker arm plumb (reach arm), then see how the 
valve on opposite cylinder is for lead; if equal at 
both ends, the valve is set, if not, adjust the jamb 
nuts to suit. Do the same on the other pump. 

Q.—Does the duplex pump exhaust its steam 
through the same port that it enters and thence 
through the cavity under the valve to the exhaust 
chamber as in the common slide-valve engine? 

A.—No. It has a separate steam and exhaust 
port at each end. (See cut, page 76.) 

Q.—How does it work? 

A.—The piston covers and closes the exhaust 
before it reaches the end of its stroke, and the 
steam left in the cylinder acts as a cushion. At 
the end of stroke the steam valve opens and the 


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76 





































































































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FEED PUMPS 


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15. Piston Body. 3 °* Lower Rock 





78 QUESTIONS AND ANSWERS 

live steam forces the piston back. -The same at 
both ends. 

Q.—Why does the piston with the long lever 
move in the same direction as the opposite valve, 
while the other piston with short lever and the 
opposite valve rod move in opposite directions to 
each other? 

A.—The lever last mentioned (indirect motion) 
starts the opposite piston on the reverse stroke, 
and this piston on reaching the end of the stroke 
opens the valve for the other piston to reverse. 

Q.—Why is this arrangement made so? 

A. —Because it is necessary to secure the reversal 
of the pumps, which could not be done in any 
other way as simple. 

Q.—What gives the most trouble about a 
pump? 

A.—Leaks, in one way or another. 

Q.—What would you call a good vacuum in a 
suction pipe? 

A.—About 28 inches by gauge. 

Q.—What is the proper size of suction pipe in 
a pump? 

A.—It should be full size of opening in pump. 

Q — Suppose the suction pipe was air-tight and 
only 18 inches vacuum showed on the gauge, 
where would you locate the trouble? 

A. —This would show that the water valves leak 
§0 as to destroy the vaeuujjj. 


FEED PUMPS 


79 


Q.—Would a leaky plunger show the same effect? 

A.—Yes. 

Q.—Would a leaky water end of a pump cause 
any unnecessary waste of steam? 

A.—Yes; a pump would have to work at greater 
speed to keep the boiler supplied with water, than 
otherwise required, and this means a waste of 
steam. 

Q.—Upon investigation what would you find to 
be the trouble? 

A.—The water end improperly packed or no 
packing. 

Q.—Suppose the pump used a good deal of 
steam and still went very slowly, causing great 
friction, to what would you lay the trouble? 

A. —To the pump being packed too tightly. 

Q.—How should the rings be fitted to prevent 
the friction? 

A. —Cut the ring joints a little short to allow for 
expansion when wet or under pressure. 

Q. —How would you try the pump to know that 
the packing is in good order? 

A. —Close the delivery valve near the pump, let 
plunger make a stroke up and down. If then the 
pump stops of its own accord the plunger is well 
packed. 

Q.—Is there any danger of bursting the pipe? 

A.—No, for the pipe and valve should be able to 
withstand the pressure. 


So 


QUESTIONS AND ANSWERS 


Q. —Is the pressure greater in the pipe than in 
the boiler; if so, what causes it? 

A.—Yes, as there is more area in the steam 
cylinder. 

Q.—How many valves has a duplex pump, and 
how many stories? 

A.—The duplex pump has eight valves and two 
stories, four valves to each story, one story above 
the other. 

Q.—Where are the receiving valves located in a 
3x4x6 inch duplex, also the discharge valves? 

A.—The receiving or suction are the lower set 
and the discharge the upper set. 

Q.—How would you partition off the valves in 
the water end of a double-acting pump? 

A.—Place the partition between the suction 
valves only. 

Q.—How many ports has each steam cylinder 
of a duplex pump? name them. 

A.—There are five, namely, two steam, twc 
exhaust and one outlet port to the atmosphere. 

Q.—How wide are the steam, exhaust and out¬ 
let ports of a duplex pump 3x4x6 inches and how 
thick are the dividing ribs? . 

A.—The steam and exhaust ports are 7-16 of an 
inch, the outlet (in the center) is 9-16, and the ribs 
yi inch each. 

Q.—How long is the exhaust cavity in the middle 
of steam slide valve? 


FEED PUMPS 


8 l 


A.—It is i and 9-16 inches long. 

Q.—How long are the two faces at each end of 
valve? 

A.—They are each the same length as exhaust 
cavity. 

Q.—How much lap has the valve at each end 
over the steam ports when in central position? 

A.—Three-sixteenths of an inch. 

Q.—How much lap has the exhaust? 

A.—None; the valve just seals the two exhaust 
ports. 

Q.—Why do large pumps have many small 
water valves? 

A.—So the loss of water will not be so great in the 
rise and fall of the valves when the pump is working. 

Q.—How is a vacuum created in a pump 
cylinder? 

A.—There is not a real vacuum at any moment; 
the water follows the piston as fast as it moves, 
driven by the 14.7 lbs. per sq. in. pressure of the 
atmosphere. 

Q.—To what height would the water follow the 
piston? 

A.—To the height of 33 feet. At this point the 
column of water in the pipe would have the same 
weight as a column of the atmosphere with the 
same cross section area. 

Q.—Why is a check valve placed near the boiler? 

A.—To retain the water in the boiler, in case the 


82 


QUESTIONS AND ANSWERS 


pump or injector is to be disconnected for repair¬ 
ing or the like. 

Q.—What, if there were no check valve? 




nBall Check Valve. 


Horizontal Check Valve. 


A.—The pump could be run, but the discharge 
valve would seat too hard and would wear out too 
soon. 

Q.—What is done when the check valve needs 
repairing? 

A.—The gate valve between the check valve 
and the boiler is closed. 

Q.—Are angle check valves and vertical check 
valves used with boilers? 

A.—Rarely; they are mostly 
used for connecting a steam 
heating system to the traps in 
the boiler room. 

Q.—How much lift should a 
check valve have? 

A.—Enough to give an area 
of opening, equal to the area of 
the feed pipe. 

Q.—Is it well to give it a 
larger lift? 



- Sectional. 

“ Clip” Gate Valve 











FEED PUMPS 


83 



Angle Check Valve. Vertical Check 
Valve. 


A.—No; too much lift wears valve and seat. 

O.—What is the use of the pet cock? 

A.—If the pump is in good order, the pet cock 
will show full stream at forcing and weak at suc¬ 
tion. It shows tank or hydrant pressure both 
strokes, when receiving valve is held open by dirt, 
etc. It shows boiler pressure both strokes when 
check and discharge valves do not work properly. 

Q.—What is the air chamber’s duty? 

A.—The elasticity of the air in it renders the 
pressure and flow practica’ly uniform, notwith¬ 
standing the intermittent action of the force. It 
furnishes what in electricity would be called a 
constant potential service. It also renders the 
seating of the valves more even. 

Q.—What are the features of a Fire Engine? 

A.—A fire engine consists essentially of a pair 
of single-action suction and force pumps. The 
boilers are tubular, of sufficient capacity to work 
the pumps 500 strokes per minute. The working 
pressure of steam is usually 80 to 100 lbs. per 
square inch. 










THE ARTESIAN 
PUMP 

The engine part of the 
artesian pump shown in 
the cut, is a common ver¬ 
tical slide valve engine in 
its cylinder parts. 

The figures indicate the 
parts as follows: 

1 . Steam Cylinder. 

2 . Steam Cylinder Head. 

4 . Steam Piston Head. 

5 . Follower Head. 

6 . Inside Piston Ring. 

7 . Outside Piston Rings 

8 . Adjusting Screw. 

9 . Jam Nut. 

10 . Adjusting Spring. 

11 . Cap Screws for Fol¬ 

lower. 

12 A, B. Piston Rod. 

13 . Brass Piston Rod Nuts. 
14 Steam Slide Valve. 

15 . Steam Chest. 

16 . Steam Chest Cover. 

17 . Upper Stem Gland. 

18 . Bower Stem Gland. 

19 . Gland Studs. 

20 . Steam Valve Stem. 

24 . Stem Guide on Cylin¬ 

der. 

25 . Brass Jam Nut. 

26 . Brass Split Nut. 

27 . Brass Tappet Head. 

28 . Tappet Head Bolt. 

29 . Stem Link. 

31 . Fulcrum Bolt. 

32 . Stem Guide. 

33 . Stand. 

34 . Piston Rod Gland. 

36 . Swinging Arm. 

38 . Crosshead Link. 

40 . Crosshead with Bolts. 

41 . Crosshead Jam Nuts. 

46 . Suction Flange in the 

Base. 

47 . Discharge Flange. 

48 . Hinge Boll and Nut. 

55 . Base Stuffing Box 

Gland. 


84 

















































STEAM PUMP GOVERNOR 


Description.— The upper wheel i in yoke is the 
lock nut. Turn it to the left; then turn lower 
wheel 2 to the right, which 
raises and opens the double 
steam valve 8; when partly 
open, open the throttle valve 
and start the steam pump. 

Now close angle valve 4 and 
open globe valve 5. This lets 
the main water pressure on the 
piston 6 and spring 3 in brass 
water cylinder 7. Now regu¬ 
late by screwing up or down on 
wheel 2 until the water pressure 
gauge shows pressure desired 
to carry; then set in place by 
turning wheel 1 to the right 
until up against bottom end of 
the piston rod. 

To Operate. —In starting or 
stopping the pump do it with pump governor 
the main steam throttle. Do not change the 
adjustment of the governor. In starting, close 
globe valve 5 and at the same time open angle 
valve 4. As soon as started, close angle valve 4, 
85 





















86 


PUMP GOVERNOR 


open globe valve 5 and pump will hold the pressure 
at which it is set. 

Packing Governor, Etc. —Pack the valve rod as 
light as you can and screw stuffing box nut down 
lightly with thumb and finger, just enough to 
stand the strain. Do not use wick packing, but 
some good sectional, square or round packing. 

To Clean and Oil Governor. —Once a month 
run the pump by the throttle, shut off ..both valves 
4 and 5, then open union 9, take off water 
cylinder cap n, take out piston 6, also stem and 
steel spring 3, wipe out the cylinder 7, clean piston 
head 6, and oil them with some good oil that will 
not gum. If governor is kept clean and attention 
paid according to directions no trouble will arise. 

To Connect. —Place governor between the steam 
chest and throttle valve so it will stand plumb; 
connect bottom outlet flange or screw with steam 
pipe on steam chest, then connect the boiler pipe to 
inlet, placing throttle in most convenient place. 
Use short nipples so as to place governor as close 
to steam chest as possible. 

To Connect Water Part.— Tap the discharge 
main or pipe, if horizontal, on the side for % inch 
pipe, run pipe up about a foot higher than top of 
pipework of governor, then over to it arid down 
and connect to quarter-inch valve on top of pipe¬ 
work over governor. If for two governors on 
pumps discharging into same main tap, the same as 


PUMPS 


87 


for single governor and run up and over between 
governors, then put on a “T,” and run to right 
and left till over pipework above each governor 
and connect. If the pulsation of pump is noticed 
it can be avoided by partly closing globe valve 5. 
Never connect close to air chamber. Insert a 
short piece of pipe in drip “T” 12 at bottom of 
brass cylinder to reach the floor. 

DOUBLE ACTION WATER PUMP WITH 
ROLLING VALVES 

(See page 88) 

A double action water pump, built in two 
pieces. A, the upper or main part, contains the 
delivery valves c,d, and the pump barrel c, which 
is made of a seamless drawn brass tube. (Fig. 2.) 

The lower part contains the chamber B, to 
which the suction pipe is connected, and the 
suction valves a, b. It is bolted to A by bolts e, f. 

The plunger, D, is provided with two reverse 
cup leathers. E, the plunger rod, passes through 
the stuffing box F. 

The downward stroke of D opens the two 
valves a and c, while it closes b and d. The 
upward stroke acts in the opposite sense. 

The deep well plunger, Fig. 1, consists of the 
brass pump cylinder A, the pump case B, the air 
barrel D, and the water pipe E connecting pump 
to stuffing box; c is the suction valve, b the deliv¬ 
ery valve, f the suction strainer. 





% 





88 














































































































































































































































































































































THE BOURDON STEAM SPRING GAUGE 



VIEW OF INNER PARTS 


Description. —A brazed, tempered-brass tube, 
bent in an almost complete circle, has the open 
end attached to one arm of a siphon pipe, while 
its closed end is fastened to a lever. The steam 
pressure on the water, in the pipe and tube, tends 
to straighten the tube or spring (by pressing more 
against the outer curve than the inner), moving 
the lever, the long arm of which turns, with its 
toothed arch, the hand of the dial, indicating the 
pressure per sq. inch of boiler. 

Q.—Why is water kept in the spring and siphon? 

A.—A direct contact with steam would take the 
temper out of the tube. 

Q .—How is a vacuum gauge constructed? 

89 


9 o 


QUESTIONS AND ANSWERS 


A.—It has a lighter spring and it acts in the 
reversed sense as the atmospheric pressure tends 
to bend it more, the less pressure there is inside, 
or . in other words, the greater the suction. The 
dial plate is graduated to register 30 inches of 
vacuum to equalize 15 lbs. of atmospheric pres¬ 
sure or a column of mercury of 30 inches. 

Q.—Explain the compound ammonia gauge? 

A.—It is the same style as a steam gauge, only 
the spring is of steel tubing and the graduation on 
the dial is to show both ways from zero mark. All 
figures above show pressure and all below show 
vacuum. 

Q.—Why is the ammonia gauge spring made of 
steel instead of brass? 

A.—Because the ammonia destroys brass, while 
steel is not affected by it. 

Q.—Are there two springs in the compound 
ammonia gauge? 

A.—No; it is so named because it shows either 
vacuum or pressure on the same dial with the 
same needle. 

Q.—What is a duplex gauge? 

A.—It has two springs and two needles, one 
showing the excess pressure, and the other train 
pipe pressure. They are used on locomotives only. 


THE LUBRICATOR 


Q.—Of what use is a lubricator? 

A.—It supplies the valve, piston and cylinder 
with oil automatically after the drop feed is set. 



Q.—How many different styles of lubricators are 

there in use? 

A.—There are three—single feed for stationary 
9i 
























9 2 


QUESTIONS AND ANSWERS 


engines, double feed for compound and locomotive 
engines, and triple feed for triple expansion, and 
locomotive engines and air pump. 

Q.—How does a lubricator do its work? 

A.—As seen in the cut, by the condensed water 
passing down the center water pipe from the con¬ 
dense chamber to the bottom of the oil reservoir, 
forcing the oil to the ^top and down the oil pipes 
to and through the feeder valves C, C. After 
passing the feeder valves, the oil floats up through 
the water in the sight feed glass and on reaching 
its surface is carried off horizontally through the 
choke plug (P) by steam from pipe E. 

Q.—How is the lubricator attached to the 
system? 

A.—Connect its top to the live steam pipe and 
the feed pipe further down. 

Q.—What precaution should be had after 
attaching? 

A.—The passages and connections of the lubri¬ 
cator should be blown out with steam. 

Q.—How is a lubricator filled? 

A.—Close all the feeder valves C, C, also the 
live steam connection, then open blow-out valve 
D, and fill through filler plug. 

Q.—How is the feed stopped and started? 

A.—By closing and opening the valves C, C. 

Q.—Supposing the lubricator ran empty, how 
would you refill it? 


THE LUBRICATOR 


93 


A.—Close feeder valve C and live steam con¬ 
nection ; open blow-off D; open filler plug and as 
the water,passes out, fill in with oil. 

Q. —After filling what do you do? 


D 



A.—First, close drip D, screw filler plug in tight, 
open live steam connection fully, then regulate oil 
flow with valves C, C. 

Q.—Are the valves B, B ever closed? 

A.—No, except when a feed glass is broken. 

Q.—What is to be done, when a glass breaks? 

A.—Close valves C, C and B, B; unscrew plug of 
top bracket, loosen packing nuts and remove old 




94 


QUESTIONS AND ANSWERS 


glass. Insert the new glass, and fasten nuts and 
valves, etc. 

Q.—Is it well to reuse old gaskets? 

A.—It is not. 

Q.—Is there any difference between the single, 
double and triple lubricators? 

A. —Not in principle or operation. 

Q.—Do all lubricators work alike? 

A.—No, the down feed lubricator dispenses with 
the water in the feed glass. 

Q.—How much oil should be fed through a 
lubricator for an engine working heavily? 

A.—About 5 drops per minute. 

Q.—How many drops for small engines doing 
light work? 

A.—From 3 to 4 drops.per minute. 

Q.—What care should be taken in filling a 
lubricator? 

A.—No foreign matter must be allowed to get 
in. The opening in the feed nozzle is so small 
that almost anything would clog it. 

Q.—How large is the opening? 

A.—It is 3-32 of an inch. 

Q.—How is the feed nozzle cleared of clogging 
matter? 

A.—By shutting off the live steam connection, 
opening the blow-off and then opening the feed 
valve to allow the back pressure to pass through 
the opening. 


THE LUBRICATOR 95 

Q.—How is the choke plug cleared of clogging 
matter? 

A.—In the same way. The back pressure will 
force the matter into the feed glass. 

Q.—How large is the opening in the choke plug? 

A.—It is 3-64 of an inch. 

Q.—How can it be decided whether this opening 
is of the right size? 

A.—Start the engine. Then regulate the oil 
feed in the glass, counting the number of drops in 
one minute. Then shut the throttle of the engine 
and notice quickly whether the number of drops 
changes. The number will not change if the 
opening is of the proper size. 

Q.—Is it harmful to use more oil than needed? 

A.—Yes. It clogs up the exhaust pipe of the 
engine, decreasing its opening. The increase in 
pressure necessary for exhausting through a 
clogged exhaust pipe means larger coal consump¬ 
tion. 

Q.—Is it well to feed both valve-oil and engine- 
oil through a lubricator? 

A.—No. The mixing impairs the lubricating 
properties of the oils. Only valve-oil should be 
used for engine cylinders. 


THE ENGINE 


THE COMMON SLIDE VALVE 


Description. —When the piston is at either end 
of the cylinder, the steam port at that end is open 
a fraction of an inch (lead); the steam enters 



and starts the piston on its travel, the port opening 
wide and admitting the steam freely. The valve 
travels in the opposite direction. When the piston 
has traveled % or so of its stroke (according to 
the lap on the valve) the slide closes the steam 
port, so that during the remainder of the stroke 
no more steam enters on that end of the cylinder. 
The steam present expands, therefore, as long as 
the piston keeps moving in the same direction. 
At the moment when the piston reaches the other 

end of the cylinder, the steam port there opens 
96 




























THE ENGINE 


97 


slightly (lead), the entering steam pushes the 
piston back and the expanded steam on the other 
end of the piston escapes through the exhaust 
cavity of the valve, which at that moment con¬ 
nects the steam port with the exhaust port, and 
disconnects them again when only enough steam 
is left to serve as a compression at the point from 
which we started. The operation is the same at 
both ends of the cylinder. 

Q.—How would you proceed to set a common 
slide valve? 

A.—See that valve covers both steam ports 
equally, the crank pin at dead center, heavy side 
of eccentric up or at right angle with the crank 
pin, rocker arm plumb, at center of travel, and 
all connections close fit; move the eccentric around 
on the shaft in direction engine is to run, until the 
valve has proper opening, say 1-16 of an inch, then 
tighten eccentric with set screws, turn crank pin 
to opposite dead center and see how the opening 
is at the opposite port. If equal the valve is set, 
if not, say ^ of an inch out at one end and proper 
lead (1-16) at the other, divide the difference and 
adjust the valve 7-32 of an inch, then move the 
crank pin to. the same dead center that you started 
with and move the eccentric the same way to 
bring the valve back to 1-16 inch lead. 

Q.—How is the length of the valve stem and of 
the eccentric rod found? 














THE ENGINE 


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IOO 


QUESTIONS AND ANSWERS 


A.—Place the valve in the middle of its seat. In 
this position the rock arm is vertical. The dis¬ 
tance A between a vertical line drawn through the 
center of the rock shaft and a vertical line through 
the center of the valve is the length of the valve 
stem. The distance B between the central 



vertical of the rock shaft and a vertical drawn 
through the center of the main shaft is the length 
of the eccentric rod. 

Q.—How is a single eccentric engine reversed? 

A.—Remove the valve chest cover, measure lap 
and lead, loosen the eccentric and move it around 
the shaft to a position where the valve will show 
exactly the same as before. Then fasten the 
eccentric with the set screws in position and cover 
the valve. 

In the cut above position Ei shows the engine 
running over forward. By bringing the eccentric 
into position E2, the engine is reversed, running 
under backward. Further adjustments can then 
be made by repeatedly trying the engine from one 
dead point to the other. 








THE ENGINE 


IOI 


Q.—How would you reverse the motion of a 
common slide valve engine? 

A.—Set the crank pin on dead center, remove 
the valve chest cover and notice the amount of 
lead at steam edge of valve. Then loosen the set 
screw or key of the eccentric and turn it around on 
the shaft in the same way it has been running 
until the valve has reached the end of its travel; 
keep moving the eccentric until it has the same 
lead a5 before, then tighten the set-screw. This 
will bring the eccentric around on the shaft one- 
quarter of the circumference. 

Q.—How is a single eccentric slide valve rocker 
arm engine converted into a reversible engine? 

A.—If the valve has neither lap nor lead, it can 
be done by putting another wrist pin in the rocker 
arm, above the rock shaft center. But ^if the 
valve has outside lap, then another eccentric must 
be put on, and both eccentric rods hooked on—in 
their turn, according as the engine is to run—to 
the same wrist pin placed below the center of the 
rock shaft. 

Another way is to use the link motion, as in a 
locomotive engine. 

Q.—Which leads, the crank pin or the eccentric? 

A.—The eccentric. (See page 116.) 

Q.—At what angle does the highest-pitch line of 
an eccentric lie to the level of the crank pin at 
dead center? 


102 


QUESTIONS AND ANSWERS 


A.—About 120 degrees. 

Q.—What is initial pressure? 

A.—That which would be in the engine cylinder 
at the beginning of the forward stroke of the 
piston. 

Q.—Explain terminal pressure? 

A.—Terminal pressure is in the cylinder of an 
engine at the end of the stroke of piston if the 
exhaust valve does not open until the stroke is 
finished. 

Q .—What is meant by wire-drawn steam? 

A.—The operation of reducing the steam pres¬ 
sure between the boiler and the cylinder. 

LEAD AND LAP 

Q.—What is pre-admission or lead of an engine? 

A.—The amount of steam port opening at the 
end of the stroke of piston at either end of the 
cylinder. 

Q. —How would you give lead to a valve? 

A. —Place the eccentric ahead of its true posi¬ 
tion. (See page ioo.) 

Q.—How would you alter a valve to cut the 
steam off at a given part of the stroke? 

A.—As the case demands add lap to or take off 
from the steam edge of valve. 

Q.—What is lap? 

A.—The extra amount of valve which covers 
ports when not in mid-position. 


THE ENGINE 


IO3 


Q.—Is there any lap on the exhaust edges of 
valve? 

A.—Yes. They serve to delay and shorten the 
exhaust and thus to increase compression. 

Q.—What kind of engines call for exhaust lap? 

A. —Those having short and quick travel. They 
are heavy in weight and great in size. 

Q.—Why is lap given to a steam valve? 

A.—So the port will close before the piston 
reaches the end of the stroke and make the steam 
io work by its own expansion. 

Q.—What is meant by cut-off”? 

A.—In an engine with a 24" piston stroke it 
would mean that the steam port is closed when the 
piston has traveled 6 inches, or the first quarter 
of its stroke. 

Q. —How many expansions are there in our case? 

A.—At half the stroke 12 inches or the double, at 
18 inches the threefold and at 24 inches the fourfold 
expansion. 

Q.—How do you decide the proper amount of 
steam lap on a slide valve? 

A.—The length of the piston stroke, minus the 
part of stroke before the cut-off, is divided by the 
whole length; extract square root of the quotient. 
Multiply this square root by one-half the length 
of the stroke of the valve, and from the product 
take one-half the lead (if any), and the remainder 
will be the amount of lap required. 


104 QUESTIONS AND ANSWERS 

Example: Given a 48" stroke, travel of valve 6", 
to cut off at half stroke, no lead. Half stroke 

2 _ 

equals 24". 24 48 = .50. V 50 = .707. 

• 707 X 3 = 2.121". Ans. (Sq. root, seepage 240.) 

Q.—Should the lead and compression in the 
valve of a vertical engine be the same on both 
ends of the cylinder? 

A.—No; the lead and compression at the lower 
end of the cylinder should be greater, to make up 
(compensate) for the weight and momentum of 
the piston, crosshead and connecting rod. 

Q.—What is the difference between movable 
and fixed expansion? 

A. —Movable expansion is by separate gearing or 
valves, and fixed expansion is by lap of slide valve. 

Q.—Give another name for the expansion valve 
for cut-off? 

A.—The link motion. (See page 144.) 


COMPOUND ENGINES 

Q.—Explain the compound engine? 

A.—A compound engine is one ,that has two or 
more cylinders following in regular order having 
increasing diameters so arranged that the exhaust 
steam from the first or high pressure cylinder is 
exhausted into the second or larger cylinder to do 
work before escaping to the condenser. 



COMPOUND ENGINES 105 

Q.—Explain the special advantages by com¬ 
pounding? 

A.—First—Compounding enables the fullest 
advantage to be taken of the expansive power of 
very high pressure of steam. Second—The ease 
with which it may be adapted to work on one or 
more cranks, thereby reducing the excessive 
variation of strain which occurs in a single high 
pressure engine. 

Q.—Classify compound engines? 

A.—First—Where the pistons of both cylinders 
commence the stroke at the same time. Second— 
Those which exhaust from one cylinder before the 
next cylinder is ready to reqeive it, in which case 
the steam is retained for a portion of the stroke in 
a chamber or receiver between the two cylinders. 

Q.—What kind of engines would you call them! 

A.—Receiver engines. 

Q.—What can you say about triple and 
quadruple expansion engines? 

A.—The principles which govern the compound 
are the same in the triple and quadruple expan¬ 
sion engines. 

Q.—What is a cross compound? 

A.—It is two separate engines side by side con¬ 
nected to one shaft, one being a high pressure and 
the other a low pressure. (See cut page 10.) 

Q.—What is meant by the tandem compound 
engine? 


106 QUESTIONS AND ANSWERS 

A.—It is where the high and low pressure 
cylinders and engine frame are one behind the 
other (one following the other). 

Q.—About how high should the steam pressure 
be to run a tandem or cross compound engine with 
economy? 



NAMES OF PARTS OF TANDEM COMPOUND ENGINE 


1. 

Crank Pin. 

12. 

Cross Head. 

2. 

Crank. 

13. 

Piston Rod. 

3. 

Crank Shaft. 

14. 

Engine Frame. 

4. 

Main Rod. 

15. 

Main Cap. 

5. 

Governor (fly ball). 

16. 

Low Pressure Exhaust. 

6. 

Valve Chest Covers 

17. 

Fly Wheel. 

7 

Low Pressure Cylinder. 

18. 

Guides. 

8 

High Pressure Cylinder 

19. 

Foundation Bolts. 

9. 

Globe Valve. 

2n. 

Engine Foundation. 

10. 

Cylinder Head. 

21. 

Bottom Foundation 

11. 

High Pressure Exhaust 
Pipe. 


Bolts. 


A.—The boiler pressure should be from iio to 
125 lbs. pressure to the square inch to work well. 
For triple expansion about 180 lbs., and so on in 
proportion. 

Q-—Why is such high pressure carried for com¬ 
pound or triple expansion engines? 

A.—So the last low pressure cylinder will be 







































THE CORLISS ELECTRIC ENGINE STOP 107 

able to do work from the expafrsion of steam that 
first entered the high pressure cylinder. 

For calculating the H. P. of a compound engine, 
see page 150. 


THE CORLISS ELECTRIC ENGINE STOP 

Description: The steam valve K is held closed 
by the electro-magnet O and armature G, as long 
as the lever H is in upright position. When the 
circuit P P is closed, the upper end of lever H is 
released and steam can open the valve, forcing H 
into the position indicated by dotted lines. The 
steam is thus admitted into the cylinder A, 
closing the vertical check valve J and forcing the 
piston C upward. The end of the piston rod C 
engages the clamp D, attached to the side rod M, 
raising the governor balls N N to their highest 
position. Then check valve L closes, holding the 
governor balls in their highest position. Thus the 
grab hooks are prevented from opening the main 
valve. 

The electric circuit P P is closed at will by 
pressing a button conveniently located, or it may 
be closed automatically at any desired limit of 
speed by means of the speed limit stop attach¬ 
ment. 

This device consists of two adjustable points F 
F, electrically connected and so placed that the 




108 
























































COMPRESSION ENGINE 109 

clamp D is brought in contact with one of them 
at the highest, and with the other at the lowest, 
desired limit of speed. This contact closes the 
circuit, the lever H is released, etc., as above 
described. 

To put the engine stop in working order again, 
the lever H is replaced in the upright position, 
the drip valve I is opened to allow the governor 
balls to resume their normal position, and the 
valves are set in the proper position by rocking 
the wrist plate backward and forward. 


THE HOT AIR PUMPING ENGINE 
(See Sectional View on next page ) 

The air heated in F expands, driving the power 
piston D upward. The compression piston C 
moves downward at the same time, driving the 
cold air through H into F, thus increasing the 
pressure until its stroke is completed. Then the 
increased pressure forces the compression piston 
C up, passing back from F to C through the 
regenerator H, where the heat is absorbed by the 
regenerator plates. By this cooling the pressure 
is lowered to its minimum, the power piston 
descends and compression begins again. The air 
passing from C to F through H, reabsorbs heat 
from the regenerator plates, which helps to aug¬ 
ment the pressure in F. (Pump, see page 88.) < 



I IO 


VIEW OF COMPRESSION ENGINE 


DESCRIPTION 

A —Compression Cylinder. 

B. —Power Cylinder. 

C. —Compression Piston 

D. —Power Piston. 

E—Cooler. 

F. —Heater. 

G. —Telescope. 

H. —Regenerator. 

II—Cranks. 

JJ.—Connecting Rods. 

KK-Piston Packings. 

(Leather.) 

L.— Check 
Valve, plac¬ 
ed at back 
of compres¬ 
sion cylin- 
d e r but 
shown at 
sideon cut. 


M. —Pump Primer. 

N. —Blow-off Cock. 

OO. —Knuckles. 

PP.—Heater Bolts. 

R.—R’g’n’r’t’r Bon’et. 
SS.—P’mp V’ve B’net. 
T.—Water Jacket, to 

f irotect packing 
rom heat. 

UU.—Pump Buckets. 
V.—Pump Gland. 








































































































OILING DEVICES 


III 



The two ends of each connecting rod are con¬ 
nected by a tube A, in which is fitted a rod B, 
extending from the upper to the lower brass, and 
so arranged that one key, E, at once takes up the 
lost motion on both brasses C, D. The key is 
nicely adjusted by the nuts F, G. 


The pump plunger U U moves up and down 
with the compression piston C, to the top of 
which the plunger rod is connected. 


SIGHT FEED AND OILING DEVICES FOR ENGINE AND 
MACHINERY BEARINGS 



Cross Drip Valve. Straight Drip Valve. Angle Drip Valve. Cros^Sight-Feed 










I 12 


QUESTIONS AND ANSWERS 



A.—Regulating valve. 

B—One of the flat places to 
hold spring C. 

D.—Packing nut. 

Light glass. 


Uncle Sight Feed 
Vatve with 
Union. 


WIPER CUPS 



Sectional 
Grease Cup, 






Adjustable Wiper Adjustable Wiper Adjustable Wiper 
Cup for Cup with Elbow CupforCrank 

Wick. Shank. Pin. 


Adjustable Plain 
Wiper Cup with 
Elbow Shank. 



PlalnWiper Cup. Horijontal Wick Wiper Oil Cup Wiper Tip. Drip Trough. 

Cup.. 


CONDENSERS 

Q.—What is a condenser as applied to an engine? 
A.—It is a part of the low pressure engine and ' 
is a receptacle into which the exhaust enters and 
is there condensed. 









CONDENSERS 


JI 3 

Q.—What are the principles which distinguish a 
high from a low pressure engine? 

A.—The high pressure is over 40 lbs. and ex¬ 
hausts into the atmosphere, while the low pressure 
is below 40 lbs. and exhausts into the condenser. 

Q.—What is the object of a condenser as 
applied to an engine? 

A.—It saves a large mass of pure hot water for 
the boiler, and it maintains a constant vacuum in 
front of the piston. 

Q. —Does this vacuum aid the steam in moving 
the piston? 

A.—It does, to the amount of half the vacuum 
gauge pressure. 

Q.—How is a vacuum maintained in a con¬ 
denser for a compound condenser engine? 

A.—By the steam used being constantly con¬ 
densed by the cold water or cold tubes and the air 
pump continually clearing out the condenser. 

Q.—How does the condensed or used steam 
form a vacuum? 

A.—Because a cubic foot of steam at atmos¬ 
pheric pressure shrinks into about 1 cubic inch of 
water. 

Q.—What is a surface condenser? 

A.—It is a chamber or receiver for the exhaust 
steam, through which pass brass tubes, carrying 
the cold water which is supplied usually by a 
circulating pump. 


114 QUESTIONS AND ANSWERS 

Q. —Why is it called a surface condenser? 

A. —Because the exhaust steam is condensed by 
the surfaces of cold water tubes and then 
removed, together with the air and vapor, by 
means of an air pump. 

Q.—Where is a surface condenser most 
desirable? 

A.—Where condensed steam is used for feeding 
boilers and distilled water is used for making 
pure ice. 

Q.—Explain the jet condenser? 

A.—It consists of a chamber in which the 
exhausted steam passes through a spray or jet of 
cold water. The steam, being condensed, falls 
with the injection water into a hot well, and from 
there it is pumped out. 

Q. —Is there a valve between the pump and a 
jet condenser? If so, of what use is it, and what 
trouble is it likely to give? 

A.—A foot valve is sometimes placed between 
the pump and condenser. Its object is to close the 
condensing chamber on the down stroke of the 
bucket plunger of a single acting pump, allowing 
a partial vacuum to be maintained in case of the 
failure of a valve on the bucket. The trouble 
likely is the same that affects other water valves 
under the same conditions. 

Q.—Is it well to start the jet condenser together 
with the engine? 


CONDENSERS 


”5 

A.—No, it is advisable to let the engine make 
several revolutions first, and then open the cold 
water injection valve very gradually. 

Q.—What is meant by a vacuum? 

A.—A space void of matter. 

Q.—Can a perfect vacuum be obtained? 

A.—No, but a compound condensing engine 
exhausts about 14% out of 15 lbs. of atm. pressure 
(indicated at 28J4 inches on vacuum gauge, 2 
inches representing one pound). 

Q.—Suppose a vacuum gauge indicates 26 
inches, how many pounds would it represent? 

A.—Thirteen pounds. 

Q.—What does 13 lbs. or 26 inches vacuum 
signify to an engineer of steam? 

A.—That he may work his steam down to 4 lbs. 
before it exhausts, as the condenser utilizes 13 of 
the 15 lbs. atmospheric pressure. Without the 
condenser the engine would work high pressure. 

Q.—What is meant by the term “back pressure”? 

A.—It is the pressure that hinders the piston, 
equal to the difference between a perfect vacuum 
and what the gauge reads. 

Q.—Does a compound engine work low pressure 
when exhausting into the atmosphere direct? 

A.—No, the low pressure cylinder gets live 
steam through a 2-inch auxiliary and works high 
pressure, 


THE ECCENTRIC 


Q.—Explain the length, throw or half the 
stroke of engine (crank)? 

A.—It is the distance between the center of 
crank pin and center of shaft. 

Q.—Explain the eccentric, also its throw? 



A.—It is anything out of center, or not con¬ 
centric. It serves as a substitute for a crank. 
The throw or stroke is the distance between the 
centers. 

Q.—Explain what is understood by the travel of 
a slide valve? 

A.—It is twice the throw of the eccentric. 

Q.—If the eccentric was made a half inch 
larger or smaller and the throw left the same, 
would it affect the travel of the valve? 

A.—No; it only affects the straps. 

Q.—Why not? 

116 



THE ECCENTRIC 


117 

A.—Because the throw or stroke is the only 
point that regulates the travel of valve. 

Q.—Explain the meaning 
of direct and indirect valve 
motion? 

A.—When the two con¬ 
nections are on the same 
side of the rock shaft, they 
move in the same sense 

v direct). When they are on direct motion, directmotjon. 
opposite sides of the rock shaft, they move in 
opposite senses (compound or indirect). 

Q.—Can you set a slipped eccentric without 
moving steam chest cover, and how? 

A.—Yes. Open cylinder cocks, roll crank pin 
over in the direction engine runs till the pin is on 
“dead center,” then open throttle slightly. Roll 
the eccentric forward in the direction the engine 
runs until steam escapes from cylinder cock at the 
end where the valve should begin to open, screw 
the eccentric fast to the shaft, roll the crank over 
to the other “dead center” and see if steam 
escapes at the opposite end of cylinder; if so the 
engine is ready to run until an opportunity occurs 
to open the valve chest and examine the valve and 
set properly. 


Supper pin. 


POCK SHAFT. 




UPPER PIN. 


LOWER PIN. 


LOWER PIN. IOMK5HAFT. 





DEAD CENTER 


A simple way of finding the exact “dead center” 
of an engine is as follows: 

Place a stationary rest close to the rim’s edge of 
the fly wheel or crank disc, at the side furthest 
away from the crosshead; roll the crank pin over, 
until the crosshead is within one-half inch of the 
end of its travel in one direction; make a well- 
defined mark on the guide at the end of the cross¬ 
head ; then lay a square across the stationary rest 
and with chalk and a scriber mark the rim’s edge 
of the fly wheel or disc. 

Then roll the crank pin in the same direction 
past the center until the same end of the crosshead 
comes to the same mark on the guide, then lay a 
square on the stationary rest and scribe another 
line on the rim’s edge of fly wheel or disc. 

Then take a pair of dividers and find the middle 
between the two points just marked. This middle 
point will correspond exactly with the “dead 
center” of the engine. Mark the point with a 
center punch. 

Then roll the engine over, until the crosshead 
comes to the opposite end of the slides, and pro¬ 
ceed as before to find the “dead center” at the 
other end of the stroke. 

118 


ENGINE POUNDING 


119 

Another way is by the use of an adjustable 
spirit level. The level is adjusted to the guides 
and then the crank pin strap is adjusted to that 
level. 


ENGINE POUNDING 

Q.—Can you describe the common causes of an 
engine pounding? 

A.—Yes. 

Q. —N ame them ? 

A.—Crank pin not being square (at right 
angles, [_) with the crank, caused by faulty work¬ 
manship, an engine being out of square, lost motion 
in crank, in crosshead pin or journal boxes, leaky 
piston rings, unbalanced valve, crank disc and 
pulley wheels, valve not being properly set, poor 
lubrication, loose piston-head, water in cylinder, 
and many others. 

Q.—Can you tell whether a crank pin is out of 
square? 

A.—Yes. 

Q.—In what way? 

A. —The slightest variation can be found by a 
good spirit level, which is used as follows: First, 
disconnect the main rod from the crosshead, then 
key the rod to the crank pin so the rod can turn 
without moving sidewise; then place the rod in a 
position to move easily as the crank is turned. 



120 


QUESTIONS AND ANSWERS 


Fasten a spirit level to the rod with a clamp in line 
with the shaft (right angles with rod). When the 
crank is turned the bulb in level should not 
change. If it does the pin is not square wdth disc 
nor parallel with shaft. 

Q.—Does it make any difference if the shaft is 
not level when testing crank pin? 

A.—No; the point that the bulb in the spirit 
level moves to, when clamped to the rod, is the 
point where it should stay the full revolution. 

Q.—If the crank pin is not properly sqt, how will 
the bulb show? 

A.—It would move, and the more the pin is out 
of square, the more the bulb will move. 


LINING, LEVELING AND SQUARING AN 
ENGINE SHAFT 

Q.—Name handy tools for lining engines and 
taking measurements? 

A. -Spirit level, light chalk line, calipers, rule, 
square, slotted piece of wood for end of cylinder to 
hold line, and a tram. 

Q.—How would you line an engine, also square 
and level a shaft? 

A.—First, disconnect and remove all parts from 
crank pin to back cylinder head, then bolt a slotted 
stick to farthest end of cylinder from crank pin, to 



LINING, LEVELING AND SQUARING 121 

which attach a string and pass it over the point, 
thence through the cylinder to end of bed plate 
and fasten so it can be adjusted to the center. 



Q.—How is the adjusting done? 

A.—With inside calipers. 

Q. —From where do you line? 

A.—From the two counter-bores. 

Q.—Why center from counter-bores and not 
from the regular bore of the cylinder? 

A.—Because they are not worn, while the 
regular bore is. 

Q.—How would you square the shaft of an 
engine? 

A.—Move the crank pin both ways, forward and 
back, above the center line of cylinder. If the 
center line intersects the crank pin both times at 
the same point, then the latter is square with the 
cylinder. If not, shift the outbearing of shaft. 

Q.—How would you level the shaft? 

A.—Drop a plumb line below and near center 
line and in front of the center of shaft, then try 









122 QUESTIONS AND ANSWERS 

the pin at top and bottom—half strokes—same as 
in squaring. 

Q.—How would you know if shaft was in line 
with center of cylinder or proper height? 

A.—By placing square against disc (or crank) 
face and bringing up to line. 

Q.—How is the proper length of main rod found, 




also the clearance between the piston and cylinder 
head when engine is at either dead center? 

A. —By first finding the striking points, pushing 
the piston to one end of cylinder, then to the 
other, marking the crosshead and guide. After 
this is done find the full stroke of engine by 
measuring from center of shaft to center of crank 
pin. The distance found is one-half of stroke. 
The difference between full stroke and the two 



























































LINING, LEVELING AND SQUARING 123 

striking points is full clearance for both ends. 
After this is known move the crosshead (with 
piston attached) back from striking point one-half 
of full clearance, which will give an equal 
clearance for both ends, viz.: Distance between 
striking points is 17% inches, stroke of engine 16 
inches, full clearance 1 % inches; the half will be 
% inch clearance at each end of cylinder. Then 
place the crank pin on same dead center at which 
the crosshead is placed and measure the length of 
rod with a tram from center of crank pin to center 
of crosshead (wrist) pin. 

Q.—How are the guides put in line? 

A.—For level, lay a straight edge across the two 
guides and caliper between it and the center line 
the whole length of the guides. For proper 
alignment across, caliper between the guide edges 
and the center line the whole length. 

Q.—What do you do, after the guides are 
properly lined? 

A.—Remove the line. Place the piston in the 
cylinder and place the crosshead on the piston, 
keying it on, or screwing it on as the case may be. 
Then line the piston rod by the guides for level 
and sideways at both ends of guides. 

Q.—What do you do when the cylinder is worn 
so that the piston center is out of line. 

A.—Put shims of tin under the spider between 
the lugs and bull ring, until the piston center is 


124 AUTOMATIC SHAFT GOVERNOR 

central, then adjust the packing rings by the 
setting out or tension springs. 

Q.—How do you line the crank pin with 
cylinder? 

A.—Place the connecting rod on the crank pin, 
and key up the brasses until they hug the crank 
pin snugly. Then move the crank pin to one of 
the dead points, and measure with inside calipers 
how far the side of the brasses on the opposite end 
of the rod is from the guide. Then move the 
crank to the other dead center and measure the 
distance on the other end of the guide. If these 
two distances are the same, the crank pin is per¬ 
fectly in line. 

AUTOMATIC SHAFT GOVERNOR FOR 
SIDE CRANK ENGINE 

Description: In following cut, A indicates the 
hole in the tripod (a seat or instrument with three 
feet or arms) B, through which the engine shaft 
passes. The eccentric C is hung to the long arm 
of the tripod B by a stud and secured by a screw 
with washer. The hole through the eccentric is 
much larger than the shaft, which permits the 
center of the eccentric to shift across the shaft, 
thus varying its throw. The eccentric is supported 
and guided by a gibbed rebate fitting over a project¬ 
ing lip on the tripod. The dead wheel D is fitted 
loosely on the hub of the tripod so that it may 



FOR SIDE CRANK ENGINE 


I2 5 


remain stationary while the tripod turns within it. 
The weights E, E are pivoted to the dead wheel 
by pins, fastened with set screws, and are con¬ 
nected with studs to the short arms of the tripod 



by the weight links F, F. The springs G, G are 
pivoted to the weights by their rods, and rest 
upon lugs on the arms of the dead wheel. They 
are precisely alike, acting together as one. The 
weights and weight links, as well as the springs, 
are duplicated only to secure more perfect balance 
of the governor. The eccentric link H connects 
the eccentric with the rim of the dead wheel by 
pins, which are made tapering to provide means 
for taking up the wear. O, O, O, O, O represent 
oil holes in dead wheel. 






126 AUTOMATIC SHAFT GOVERNOR 


To Set the Valve: The governor should set 
on the shaft so that the center of the long arm of 
the tripod, to which the eccentric arm is attached, 
is on the other side of the main shaft, directly 
opposite the crank pin, and keyed in that position. 

The steam valve that the governor controls 
should be adjusted to uncover the ports an equal 
distance on each end and should be set (while 
the weights are blocked out) as close to the rim of 
the dead wheel as the set-screw in the outer side 
of one of the weights will allow them to go. 

Place the engine crank pin on the inner dead 
center and allow the valve to just cover the steam 
port at the outer end of the cylinder; that is, the 
outer end (edge) of the valve being line and line 
with the outside edge of the outer port. Turn the 
crank pin (or engine) fn the direction it is to run 
(over or under) to the outer center, and the inner 
end of the valve should correspond in like manner 
with the outside edge of the inner port. If it does 
not, equalize the difference by the nuts on the 
valve rod. 

Roll the engine to the inner center again to be 
certain that the adjustment is right, and when 
this is accomplished the valve is correctly set. 

The governor should be so placed on the shaft 
that the eccentric is exactly in line with the valve 
crosshead pin and does not touch the sicle of the 
giam shaft bearing. 


FOR SIDE CRANK ENGINE 127 

Management and Care: All movements from 
the steam valve to the governor parts should be 
free, smooth, and without lost motion. To have 
the governor in order keep it clean and all pins 
and bearings well oiled. 

The cut shows five oil holes through the rim of 
the dead wheel, marked O. There are also two 
in the hub. These are closed with plugs which 
are removed when oiling. Use good oil and oil 
frequently. Should the governor work irregularly 
or fail to control the engine the cause will usually 
be found in some dry joint or place that binds. 

When there is a set screw on the inner side of 
the weight it is to limit the travel toward the hub, 
and should never be removed or disturbed. The 
governor key should fit closely on the sides of the 
keyway, but never on the top and bottom, to avoid 
springing the tripod hub and causing the dead 
wheel to bind. 

If governor should become gummed from bad 
oil, take out springs, first carefully measuring 
their length in position. This precaution is 
necessary so they may be replaced exactly in the 
same position. Take out one at a time to avoid 
disarrangement. Clean with kerosene, etc. Before 
tension is again put on the springs, move the dead 
wheel back and forth to see that there is no bind¬ 
ing in any of the working parts. 

To Change Speed by changing the tension of 


128 AUTOMATIC SHAFT GOVERNOR 

the springs: To run faster, tighten; to run 
slower, loosen. Or move the weights. Never 
tighten the springs down so that their spirals 
touch each other. Never tighten or loosen the 
spring more than one inch beyond its set tension. 
If greater speed be desired than can be obtained 
from the springs and weights furnished with the 
governor, others should be. ordered from engine 
builder. Be sure to mention speed desired. 

Reversing governor and engine to run over 
or under: Remove the set-screw from the outer 
side of the weight. Disconnect the eccentric link 
H from the eccentric and from the rim of the dead 
wheel by removing the pins from the lugs b and 
d. Take hold of the rim of the dead wheel with 
a monkey-wrench and pull it around on the shaft 
as far as it will go, in the direction the engine is 
to run, and again connect the eccentric with the 
rim of the dead wheel by inserting the eccentric 
link H into the other pair of lugs marked b. and 
d, using care in replacing the pins not to drive 
them so tight as to bind. Replace the set-screw 
in the outer side of the weight in exactly the same 
position as before. This reverses the governor 
and the engine is ready for service. 

HOW TO KNOW STEEL FROM IRON 

A drop of aqua fortis turns steel brown, and 
cast - iron black, while (wrought) iron is not 
affected. 



AUTOMATIC GOVERNOR FOR SELF- 
CONTAINED ENGINES 


SUCH AS DOUBLE CRANK DISC AND TWO PULLEY 
WHEELS, ONE EACH SIDE OF CRANK PIN 

Description: In the following cut, B is the 
eccentric, hung on the hub M of the band wheel 
by a pin, which is made tapering to provide means 
for taking up the wear. The hole through the 
eccentric is much larger than the shaft and per¬ 
mits the center of the eccentric to shift across the 
shaft, thus varying its throw. Piece C is the 
eccentric arm, which transmits the shift motion to 
the eccentric through the steel bands, or ribbons, 
which are fastened by* clamps to the eccentric 
arms and by screws to the eccentric. The arm is 
securely fastened to a rocker shaft, which passes 
through one of the arms of the band wheel, and 
to which the spring crossheads D, D are also 
attached. The spring crossheads carry the 
weight bars I, I, weights G, G, and the spring 
rods J, J. The springs K, K are held by the 
spring rods and are precisely alike, acting together 
as one. The weights, as well as the springs, are 
duplicated only to secure more perfect balance of 
the governor. 

To Set the Valve: Governor should set on 


129 


130 


AUTOMATIC GOVERNOR 


the shaft so that the center of the rocker shaft, to 
which the eccentric arm C is attached, is on the 
other side of the main shaft, directly opposite the 
crank pin, and keyed in that position. The steam 
valve controlled by the governor should be 



adjusted to uncover the ports an equal distance on 
each end and should be set while the weights are 
out as far as the stops will allow them to go. 

Place the engine on the “inner” center and 
allow the valve to just cover the steam port at the 
outer end of the cylinder so the outer end of the 
valve will be line and line with the outside edge 





















•FOR SELF-CONTAINED ENGINES 131 

of the outer port. Turn the crank pin in the direc¬ 
tion it is to run to the “outer” center, and the 
inner end of the valve should correspond in like 
manner with the outside edge of the inner port. 
If it does not, equalize the difference by the nuts 
on the valve rod. 

Roll the engine forward again to the “inner” 
center to be sure that the adjustment is right, and 
when this is accomplished the valve is set. 

Management and Care should be the same as 
for side crank engine governor. 

To Change Speed: Same as for side crank 
engine governor. The speed may also be changed 
by altering the positions of the weights on the 
bars. Sliding them toward the spring crossheads 
increases the speed, and in the opposite direction 
decreases it. 

Should a greater speed be desired than can be 
obtained from the springs and weights furnished 
with the governor, see instructions for speed 
changing on side crank engine governor. 

To Reverse governor for running over or under: 
Remove the eccentric strap, then take out the key 
from the governor band wheel, slip the wheel out 
to the end of the shaft, remove the taper pin oh 
which the eccentric swings, move the eccentric to 
the other hole in the hub, replace the taper pin in 
the eccentric, using care that it is not screwed in 
so tight as to bind, change the weight bars to the 


I 3 2 


AUTOMATIC GOVERNOR 


other ends of the spring crossheads, reversing their 
positions, loosen the nuts that hold the tension on 
the springs, being careful to measure the springs 
before removing the nuts, so as to replace them in 
exactly the same positions. 

After the springs are free from tension take out 
the small split pins that hold the ends of the 
spring rods in their places, remove both spring 
rods and turn them end for end, then replace the 
split pins. 

Before tension is again put on the springs, move 
the weight bars back and forth to see that there is 
no binding in any of the working parts. Also see 
that the eccentric travels its entire throw across 
the shaft, and that both of the lips strike the top 
plate that is bolted to the face of the wheel hub, 
back of the eccentric. Should the eccentric strike 
on one point and not on the other, loosen the 
clamps that hold the steel bands, or ribbons, move 
the eccentric just far enough to enable both points 
to touch, then refasten the clamps. 

Should the set-screws under the spring crosshead 
strike before the eccentric touches the stop, adjust 
them accordingly. 

Place the required tension on the springs, slip 
the wheel back to its place, drive in the key, 
replace the eccentric strap and the engine is ready 
to start. 


BALANCED SLIDE VALVE 




Q.—What do the following cuts represent? 

A.—The balanced slide valve of an automatic 
self-contained engine, protected from steam 
pressure by a hood. 


Q.—What does the first cut represent? 

A.—It is the valve and seat with hood detached. 


Q.—What does the second cut represent? 

A.—A section through the valve and hood on the 
line A B, shown in the next cut. 

133 







134 


QUESTIONS AND ANSWERS 


Q.—What does the third cut represent? 

A.—It is a perspective view of the valve and 
hood complete. 



Q.—How is the balancing of valve accomplished? 

A.—The exposed ends of valves, being of equal 
area, balance each other. 

Q.—How is the pressure counterbalanced? 

A.—By recesses of equal area with the ports 
under the hood and over the valve. 

Q.—What friction is there to overcome? 

A.—The only friction is the weight of a very 
light valve. 

Q.—How is a worn valve refitted? 

A.—By scraping. 

Q.—What is provided for the case of excessive 
pressure or water in the cylinder? 

A.—The hood is set loose on the seat, and readily 
yields.* 

Q.—What guides the hood to its correct seat? 

A.—The springs and studs. 

Q.—What is the port action of the valve? 

A.—It is that of any plain slide valve. 

Q.—What quickens the opening and closing of 
the ports? 



CORLISS ENGINE 


135 


A.—The recesses in the hood over the valve. 

Q.—What advantage has this valve? 

A.—All the advantages of a perfectly balanced 
slide valve. 


CORLISS ENGINE 

The Corliss valve gear is a detachable gear. 
There are four valves—two steam valves and two 
exhaust valves all connected to one center wrist 
plate. The wrist plate pin is connected to rocker 
arm by reach rod, and from there to eccentric by 
another rod. 

6 , 6. Exhaust valves. 

7. Wrist and rocker con¬ 
necting rod. 

8 , 8. Dash pots and rods. 

9. Eccentric rod. 

10. Governor belt and 
pulleys. 

11 . Eccentric and strap. 


1. Fly ball gov. 

2. Gag pot. 

3. Gov. stand. 
3A. Bevel gear 

case. 

4. 4. Gov. rods. 
5,5. Steam 

valves. 



12. Rocker arm. 

13. Wrist plate. 

14. Cylinder Bracket. 

15.15. Steam valve (adjust¬ 
ing) rods. 

16.16. Exhaust valve rods. 

TYPICAL CORLISS VALVE GEAR 

To Set Valves, take off the back caps or back 
heads of all four valve chambers. Guide lines 
will be found on the ends of the valves and 
chambers, as follows: On the steam valves, lines 



1 3 6 


CORLISS ENGINE 


indicating the working edges of the steam ports; 
on the exhaust valves and ports, guide lines for 



the purpose of setting them. As stated before, the 
wrist plate is centrally located between the four 


valve chambers on the valve gear side of the 



cylinder. A well-defined line will be found on 
the bracket which is bolted to the cylinder, and 



























































































CORLISS ENGINE 


137 


three lines on the hub of wrist plate, which, when 
they correspond with the single line on the 
bracket, show central position of the wrist plate, 
and the extremes of its throw or travel both ways. 

To Adjust the Valvc first unhook the reach 
or carrier rod connecting the wrist plate with 
rocker arm, then hold the wrist plate in its central 
position. 

The connecting rods between steam and 
exhaust valves and wrist plate are made with right 
and left hand screw threads on their opposite ends, 
and provided with jamb nuts, so that by slacking 



the jamb nuts and turning the rods they can be 
lengthened or shortened as desired. By means of 
this adjustment set the steam valves so that they 
will have % inch lap for 10 inch diameter of 





































i3» 


CORLISS ENGINE 


cylinder, and y 2 inch lap for 32 inch diameter of 
cylinder, and for intermediate diameters in, pro¬ 
portion. 

For the Exhaust, set them with 1-16 inch lap 
for 10 inch bore, and inch lap for 32 inch bore 
on non-condensing engines, and nearly double this 
amount on condensing engines for good results. 
Lap on the steam and exhaust valves will be 



CONNECTION 


POT ROD 


LIFTING 


CORLISS 

KNOCK-OFF CAM DISENGAGING 

stud CUT off 
GEAR 

SPRING 


STUD 


CAM 
K 

LEVER 


3>EAM 


Olt 

OR ROOM 


01b 


shown by the lines on the valves being nearer 
the center of the cylinder than the lines on the 
valve chambers. 

Having made this adjustment of valves, the rods 
connecting the steam valve arm with the dash pot 







CORLISS ENGINE 


139 


should be adjusted by turning the wrist plate to 
its extremes of travel and adjusting the rod of each 
valve so that when it is down as far as it will go 
the square steel block or stud die on the valve 
arm will just clear the latch die on the latch hook. 

If the rod is left too long the steam valve stem 
would likely be bent or broken; if too short, the 
hook will not engage, and, consequently, the valve 
will not open. 

Having adjusted the valves as stated, hook the 
engine in, and, with the eccentric loose on shaft, 
turn it over and adjust the eccentric rod so that 
the wrist plate will have the correct extremes of 
travel, as marked on the wrist plate hub. 

If marks on wrist plate do not agree at each ful 1 
throw with bracket marks, disconnect strap from 
eccentric rod and adjust the screw on stub end, as 
required, until marks do agree, both forward and 
backward; then place the crank on dead center 
and turn the eccentric in direction engine is to 
run, until an opening of 1-32 or 1-16 is shown at 
steam valve, then throw crank pin on other dead 
center to secure the desired lead in opposite 
motion. If lead is not the same,, adjust by 
lengthening or shortening the connecting rods 
between the eccentric and wrist plate as the case 
may be. 

To Adjust the Rods connecting the cut-off or 
tripping cams with the governor, have the gov- 


140 


CORLISS ENGINE 


ernor at rest and the wrist plate at one extreme 
of its travel. Then adjust the rod connecting 
with the cut-off cam on the opposite steam valve, 



CORLISS 


VACUUM 


ENGINE 


DASH POT. 


LEATHER 

ACKiNQ 


UST COVER 


so that the cam will clear the steel or latch die on 
the tail of the hook about 1-32 of an inch. Turn 
the wrist plate to the opposite extreme of travel 
and adjust the cams for the other valves in the 


same manner. 
















































































CORLISS ENGINE 


HI 

To Equalize the Cut-off and test its correct¬ 
ness, hook the engine in and block the governor 
up about halfway in the slot, which will bring it 
to its average position when running. Then turn 
the disc slowly in the direction which it is to run, 
and note the distance the crosshead has traveled 
from its extreme position at dead center when 
the cut-off cam trips or detaches the steam valve. 
Continue to turn the disc beyond the other 
dead center and note the distance of crosshead’s 
extreme travel when valve drops. If distance is 
the same the cut-off is equal; if not, adjust either 
one or the other of the rods until the distance is 
the same. 

REVIEW 

Q.—Will the cut-off mechanism unhook when 
governor is down? 

A.—No; it keeps the valve hooked up full stroke. 

Q.—Will the latch die hook on stud die of valve 
when dash pot rod is too short? 

A.—No. 

Q.—How long should the rod be? 

A.—It should be long enough so when the 
plunger is at the bottom of dash pot the latch 
would hook over the latch stud (steel block) and 
the stud lie clear of the latch (hook). 

Q.—What prevents the dash pot rod from break¬ 
ing or bending? 


142 QUESTIONS AND ANSWERS 

A.—The cushion of the plunger on air in the 
dash pot. 

Q.—Have the plungers any packing to make 
them close fit? 

A.—Yes; some have leather packing, others 
have piston rings. 

Q.—How is the air regulated in the dash pot? 

A.—By means of an air valve in the air opening 
by turning a screw in the escape hole. 

Q.—What keeps the governor in regulation so it 
will not allow the engine to run away or be over¬ 
sensitive? 

A.—A small oil reservoir on engine frame below 
governor, known as the gag pot. 

Q.—What kind of oil is generally used in the 
gag pot? 

A.—Kerosene oil. 

Q.—How would you give the governor more 
freedom of motion? 

A.—By removing one or more of the small 
screws in the piston plunger of gag pot. 

Q.—How would you warm the cylinder of a 
Corliss engine before starting? 

A.—By first blowing all the condensed water 
out of the steam pipe by means of the drip valve 
provided on the steam valve elbow or globe; then 
open the steam valve a little to allow the valves 
and cylinder to become warm. Unhook rocker 
reach rod, and work valves with wrist plate by 


CORLISS ENGINE 


143 


hand with lever. The cylinder soon becomes 
warm and all water is expelled into the exhaust 
pipe, the exhaust drain cock having been left 
open to allow the condensed water to escape. 

Q.—Would you then start the engine up lively? 

A.—No. Let engine move slowly until satisfied 
all is right, then open throttle gradually until 
wide open. 

Q.—Suppose the governor belt connection broke, 
would the engine run away? 

A.—No; the trips or safeties would slip in 
between the latqhes and dies and prevent valves 
from opening or latches hooking on to latch dies. 

Q.—Suppose the governor of a Corliss engine 
would allow the speed to fluctuate from one 
extreme to the other, where would you look for the 
trouble? 

A.—The oil gag pot in connection with the 
governor will very probably be found to be 
empty, on inspection. 

Q.—In the majority of cases where the governor 
gives trouble, what would you lay it to? 

A.—Not getting proper oiling, being dirty, oil 
holes plugged and not good enough connection to 
the main shaft. 

Q.—About how many oil holes has a Corliss 
governor, all told? 

A.—From 10 to 13. 


LINK MOTION AND VALVE SETTING 


In the position of the link shown in the cut, the 
valve has its shortest travel. The further removed 
the link is from the position shown, either upward 
or down, the longer is the valve’s travel. 



ward over eccentric. 


Ei E2. Link Blades. b. Heaviest side of forward 
under eccentric 

For valve setting in a stationary engine, 12x24 
inches, place the valve central over the ports, the 
rocker arm plumb, the heavy side of the eccentric 
plumb over the shaft, and the crank pin at dead 
center. See that the eccentric blades are con¬ 
nected with the link and are in full gear, forward 
or backward. This will make the extreme travel 
of the valve equal to the throw of the eccentrics. 
If a lead of 1-16 of an inch is desired, move the 
eccentric in the direction in which you want the 

engine to run, until your valve has the desired 
144 



LINK MOTION AND VALVE SETTING 145 

lead. Then fasten the eccentric, throw the crank 
pin on the opposite dead center and if the lead on 
the opposite port is then the same, the valve is 
set. If it is not, make adjustments. 

The above covers one motion. For the opposite 
motion reverse the link and go through the same 
operation for the other eccentric. 

For convenience an engineer should tram his 
valve-stem, so as to know the opening point 
either way without removing the valve chest cover. 

Q.—Why is a link placed on an engine? 

A.—Because it is the most convenient means 
for reversing an engine. It is almost a necessity 
where a valve has much steam lap, or where 
quick reversing is required. 

Q.—Which way does the engine run when the 
link is fully down on the block? 

A.—It would run under, toward the cylinder. 

Q.—How would you reverse the engine in that 
case? 

A.—By pushing it full up. 

Q.—How can a single-eccentric engine be made 
to be easily reversible? 

A.—By substituting a rocker arm with another 
rocker pin above the center of rock shaft. (See 
page 101.) 


HORSE POWER 


Coal furnishes heat; heat converts water into 
steam; the steam ,drives the piston; the piston 
motion is converted into rotary motion by the con¬ 
necting rod and crank pin. The rotary motion is 
utilized for work. The amount of work that an 
engine can do is expressed in “horse-powers,” the 
unit being determined as follows: 

The usual traveling gait of a horse hitched to a 
light sulk)’- is about 5 miles an hour, or 440 feet per 
minute. If a spring scale be attached to the 
singletree we may note the amount of powder the 
horse is exerting. Assuming this to be 75 lbs. 
and the speed 440 feet, multiplied by 75 lbs. equals 
33,000 foot lbs., which represents a horse-power. 
In applying this to a steam engine we first find 
the area of the face of piston head, multiply the 
answer by piston speed in feet per minute, and 
divide by 33,000; the answer will be nominal 
horse-power. For the actual or effectual horse¬ 
power take 2-3 of the quotient. 

Example: Engine cylinder 12x24, speed 100 
revolutions per minute, steam 80 lbs., area of 
piston 113 square inches. Multiply 113 by 80, 
146 


HORSE POWER 


147 


equals 9,040 lbs. pressure on piston face, by 400 
feet piston travel per minute, equals 3,616,000, 
divided by 33,000 equals 109 N. H. P. full opening 
of valve, deduct 1-3 for cut-off, equals 72 2-3 
actual h. p. For short cut-off one-half. The 
reduction is made for average pressure, condensa¬ 
tion, friction, etc., and will be found quite correct 
in practice. 

A quick rule is to square the diameter of 
cylinder and divide by 5 for small cylinders, and 
by 4 for large cylinders. Example: Eight multi¬ 
plied by 8 equals 64, divided by 5 equals 12.8 h. p. 

Example: Sixteen multiplied by 16 equals 256, 
divided by 4 equals 64 h. p. In calculating h. p. 
from indicator card use actual steam pressure 
found by the indicator (see indicator). 

A waterfall has 1 h. p. for every 33,000 lbs. of 
water flowing in the stream per minute for each 
foot of fall. To figure the power of a stream we 
must multiply the area of its cross section in feet 
by the velocity in feet per minute, which gives the 
number of cubic feet flowing along the stream 
per minute. Multiply this by 62^, the number 
of pounds in a cubic foot of water, and this by the 
vertical fall in feet and we have the foot pounds 
per minute of the fall, divided by 33,000 gives us 
the horse power. 

Example: A stream flows through a flume 10 
feet wide and 4 feet deep; the area of cross section 


148 


QUESTIONS AND ANSWERS 


is 4 multiplied by 10, equals 40 feet. The velocity 
is 150 feet per minute—40 multiplied by 150 
equals 6,000, equals the cubic feet of water flow¬ 
ing per minute—6,000 multiplied by 62^ equals 
375,000, which are the pounds of water flowing 
per minute. The fall is 10 feet—10 times 375,000, 
which are 3,750,000, equals the foot pounds of the 
waterfall. Divide 3,750,000 by 33,000 and we 
have 113 21-33 as the H. P. of the fall. 

Water-wheels yield from 50 to 90 per cent of the 
water power. 

One “watt” is the 1-746 paft of one horse power. 
One thousand watts or a “kilowatt” equals one 
and one-third horse power. The watt is the 
practical unit of electrical activity or power; it is 
the rate of working in a circuit when E. M. F. is 
one volt and the current one ampere. (See elec¬ 
tricity. ) 

The best engines and boilers develop a horse 
power per hour by the consumption of 2 lbs. of 
coal. But this is better than the average, and 
3 lbs. is more common. 

Q.—How much heating surface is required to 
develop one horse power? 

A.—It varies with the purpose of the plant. 

Steam for heating, etc. 15 sq. ft. heating surface 

For plain throttle engine. 15 “ “ “ 

For simple Corliss engine. 12 “ “ “ 

For compound Corliss condensing.. IQ “ “ “ 

Q.—How many horse power will a boiler furnish 





HORSE POWER 149 

for a plain slide valve engine, boiler having 
1,500 square feet heating surface? 

A.—One hundred H. P. 

Q.—How much for simple Corliss engine, same 
boiler? 

A.—One hundred and twenty-five H. P. 

Q.—For compound engine? 

A.—One hundred and fifty H. P. 

Q.—Which would you consider the best basis in 
comparing boilers? 

A.—Their evaporative efficiency. 

Q.—Give consumption of steam per indicated 
horse power per hour for various engines? 

A. —Plain slide valve engine..60 to 70 lbs. 

High speed automatic engine. 30 to 50 “ 

Simple Corliss engine.25 to 35 “ 

Compound Corliss engine.15 to 20 “ 

Triple expansion engine_13 to 17 “ 

An engine of the proper size and in good con¬ 
dition will yield one H. P. at the lowest consump¬ 
tion. 

Q.—How would you determine the proper size 
or evaporating capacity of a boiler to supply steam 
for a given purpose? 

A.—It is necessary to consider the number of 
pounds of dry steam actually required per hour at 
stated pressure. 

Q.—What is the standard horse power rating 
for any steam boiler for common slide valve and 
Corliss engine? 

A.—For plain slide valve engine the evaporation 



QUESTIONS AND ANSWERS 


150 

is 62lbs., or one cubic foot of water per hour per 
horse power, and for the Corliss 31X lbs., or X 
cubic foot of water per hour per horse power. 

Q.—How would you figure the horse power for 
a steam boiler of any size, if you wish to run a 30- 
horse power engine for 1 hour, carrying 60 lbs. of 
steam pressure? 

A.—First multiply the pressure to be carried by 
time in minutes, 60, and divide by 30, the amount 
of water in pounds per horse power evaporated per 
hour. 

Q.—How would you proceed to find the horse 
power of a compound condensing engine? 

A.—The H. P. of a compound condensing 
engine is found by adding the vacuum to the 
average pressure in the low pressure cylinder, and 
then proceed with the same rule given above for a 
non-condensing engine. (See indicator, page 
154-) 

Q.—What is good working vacuum for a steam 
engine? 

A.—From 22 inches upward, when the barometer 
stands at 30 inches. 

Q.—Suppose the M. E. P. upon the piston is 40 
lbs. per sq. in., and the vacuum gauge stands at 
22 inches (barometer at 30 in.), what would be 
the total on one side of the piston? 

A.—50.78 lbs. per sq. inch. 

Q.—How is it figured out? 


HORSE POWER 


151 

A.—By using the following proportion: 

30 : 22 = 14.7 :x 

and adding the answer to 40 lbs. (30 represents 
the height of the mercury in the barometer). 
Therefore, our proportion reads as follows: 30 
is to 22 as the atmospheric pressure (14.7) is to 
the steam pressure. 

22 X 14.7 = 323.40 
323.40 -T- 30= 10.78 
10.78 4-40 = 50.78 

Q.—How much pressure (resistance) is there on 
the other side of the piston? 

A.—By subtracting 10.78 from 14.7 we get 3.92. 

Q.—How is the horse power found of a non¬ 
condensing compound engine? 

A.—By first finding the average area of both 
cylinders. This is done by finding the area of the 
high and the low pressure cylinders separately; 
then add them both together and divide by two. 

Q.—How is the average mean effective pressure 
found? 

A.—By finding each cylinder's average pressure, 
then adding the two together and dividing by 
two. 

Q. —After this is done, how would you proceed 
to find the gross H. P. ? 

A.—Multiply the average area by the average 
mean effective pressure (see page 159), then by 
the piston travel per minute, and divide by 33,000. 
Answer will be H. P. 


152 QUESTIONS AND ANSWERS 

Q.—Give the rule for finding the horse power of 
a belt’s transmission; also example? 

A.—Multiply the width of the belt in feet by 
the number of hundred feet the belt has traveled 
in one minute. Example: Belt 2 feet wide run¬ 
ning 150 feet per minute—2 multiplied by 150 
equals 300 h. p. 

Belting horse power of a belt equals velocity in 
feet per minute, multiplied by the width. One 
inch in length of single belt moving at 1,000 feet 
per minute per 1 inch width equals 1 h. p. For 
double belts of great length over large pulleys 
allow about 500 feet per minute per 1 inch of width 
per horse power. Power should be communicated 
through the lower running side of a belt, the upper 
side to carry the slack. 

The average breaking weight of a belt 3-16x1 
inch, single leather, is 530 lbs.; three-ply rubber 
belt, 600 lbs. The strength of a belt increases 
directly as to its width. The allowance for safety 
for rubber belts is x /% and for leather belts 1-16 
(breaking weight) in lacing. 

Q.—How is the horse power of a tubular boiler 
found? 

A.—See page 37. A short rule to find the 
horse power of a tubular boiler is: Multiply the 
square of diameter in feet by length and divide by 
constant .4. For flue boiler multiply diameter of 
shell in feet by length and divide by .4, or 


HORSE POWER 


!53 


multiply area of grate surface in square feet by 
i Yz. The answer gives the horse power. 


Table Giving Horse Power of Boilers of the 
Usual Sizes . 


Diameter 

Shell. 

Inches. 

Eength 

Shell. 

Feet. 

Number 

Tubes. 

Eength 

Tubes. 

Feet. 

Diameter 

Tubes.. 

Inches 

Heating 
Surface. 
Square feet. 

Horse Power 

60 lbs. 

Pressure. 

72 

18 

70 

18 

4 

1502 

100 

72 

16 

90 

16 

3 y 2 

1472 

98 

72 

16 

112 

16 

3 

1496 

99 

72 

15 

112 

15 

3 

1400 

93 

60 

18 

65 

18 

3>4 

1200 

80 

60 

17 

65 

17 

3>4 

II48 

76 

60 

16 

65 

16 

3/4 

1075 

72 

OO 

16 

80 

16 

3 

1088 

72 

54 

18 

50 

18 

3^4 

951 

63 

54 

17 

50 

17 

3 % 

9OO 

60 

54 

16 

50 

16 

3 /z 

795 

53 

54 

16 

60 

16 

3 

832 

55 

48 

16 

40 

16 

3 >4 

683 

46 

48 

16 

49 

16 

3 

684 

46 

48 

15 

49 

15 

3 

642 

43 

48 

14 

49 

14 

3 

600 

40 

42 

15 

38 

15 

3 

508 

34 

42 

14 

38 

14 

3 

476 

32 

42 

13 

38 

13 

3 

441 

30 

42 

12 

38 

12 

3 

408 

27 

42 

II 

45 

II 

2 J 4 

390 

26 

42 

IO 

45 

IO 

2}4 

355 

24 

42 

9 

45 

9 

2/4 

320 

22 































THE INDICATOR 

Q.—What is an indicator? 

A. —It is an instrument which records the varia¬ 
tions of pressure during the length of one stroke. 

Q.—Can you describe the instrument? 

A. —A small cylinder of exactly sq. inch inside 

diameter is connected to both ends of the steam 
cylinder, but steam is admitted from one end at a 
time only. In the small cylinder moves a piston, 
whose crosshead works a pair of light levers, the 
free end of which holds 
a pencil, which marks its 
path of motion on a paper 
clamped on £ revolving 
drum. 

Q.—How is the stroke 
of the instrument’s piston 
regulated? 

A. —By a spring of 
known tension. A set 
of such springs, each 
marked with the pressure 
for which it is intended, accompanies each instru¬ 
ment, as follows: 

For pressure up to 21 lbs. per sq. inch use 15 lb. spring. 

“ “ “ “ 94.. “ 30 

.143.50 



154 










THE INDICATOR 


*55 


Q.—What makes the indicator card revolve? 

A.—A carefully adjusted cord, indirectly con¬ 
nected to the crosshead of the engine. 

Q.—How do the pencil 
tracings on the paper convey 
information? 

A. — For 
an intelli¬ 
gent read¬ 
ing of the 
diagram 
one should 
compare it 
with the line 
the pencil 

■TZ. ■=CB» 



Q- 


would trace under 
ditions. 

would you con¬ 


struct such a perfect line? 

A.—Assuming an engine to have a 32" stroke, 60 
lbs. steam (gaugepressure), vacuum 12 lbs., cutting 
off at 8", exhaust release 2" from end of stroke, 
and compression (exhaust closure) 5" from com¬ 
pletion of stroke,—I should lay off these figures 
on a “cross-section” sheet. (Fig. 1 shows the 
cross-section in the margin only, to give a clearer 
cut. Only the principal lines are drawn all across.) 

Mark off 32 spaces, each to represent 1" of 
stroke, horizontally, calling the starting point at 
the left o and the end at the right 32. Mark off 







































THE INDICATOR 


I5 6 


vertically 25 spaces, each to represent 3 lbs. of 
pressure. The upper limit of the fifth space 
(starting from the o point first mentioned) will 
& g £ & 



then be atmospheric line (3x5=15), 5 spaces 
further will be the 15-lb. steam pressure line, and 
so on, the last line representing the 60-lb. pressure. 
























THE INDICATOR 


157 


Steam enters in our case during M of the stroke, 
therefore, we make the “steam line” 8 spaces 
long on the 60-lb. line, starting from the o 
vertical. At the end of the steam line the supply 
is cut off, expansion begins and pressure is 
reduced, first rapidly, then more and more 
slowly (in an inverse ratio to the volume; at 
point 16 the volume has been doubled and the 
pressure halved). This gives an evenly curved 
line down to the intersection of the vertical 30 (2 0 
from end of stroke) with the horizontal indicating 
6 lbs. of pressure (2 spaces above the atmospheric 
line). At this point (point of release) the release 
(exhaust) valve should open, and the pressure 
sink again rapidly down to nothing (atmospheric 
line) and below, represented by a short, sharp 
curve between the verticals 30 and. 32 and 
a straight line along the vertical 32, 4 spaces 
to the exhaust line (release line, or vacuum 
line). 

The engine piston travels then 27 inches in the 
opposite direction, while the exhaust valve keeps 
open (exhaust line) to the “point of compression” 
where the not exhausted steam begins to be com¬ 
pressed until during the last 5 inches of the 
piston’s travel the pressure is gradually brought 
up to atmospheric pressure. The “compression 
line” representing this is an upward curve ending 
at the intersection of the atmospheric line and the 


x 5 8 


QUESTIONS AND ANSWERS 


zero vertical. At this point steam is admitted, 
raising the pressure instantly to 60 lbs., shown 
on the diagram by a straight dine along the 
vertical zero up to the 6o-lb. horizontal. This 
completes the diagram. 

Q.—Does the diagram taken on engines deviate 
much from this model just described? and if so, why? 



60 


0 


ATMOSPHERE LINE. 

FIG. 2 


(The broken lines in the cut give examples of 
diagrams indicating imperfections in the cylinder 
or valves, while the outline is a nearly perfect 
diagram.) 

Q.—What is the purpose of an indicator card? 

A.—It serves as a guide in setting the valves, 
as a help (in connection with a feed-water test for 
steam-consumption) in determining the economy 
with which an engine works, and especially for 
finding the mean effective pressure of an engine. 

Q. —How do you figure the M. E, P. from an 
indicator card? 



















THE INDICATOR 


*59 


A -—Divide the extreme length of the diagram in 
io equal spaces vertically by 9 dotted lines (Fig. 2), 
and divide each space into vertical halves by full 
lines. The length of these 10 vertical lines 
(ordinates) inside the diagram indicates the M. 
E. P. for each space. Add these 10 • lengths 
together, and divide their sum in inches by 10. 
Multiply the quotient by the scale of the spring 
used in the indicator, and the product will be the 
M. E. P. throughout the stroke. 





FIG. 3 


Q.—Why do you multiply by the scale of the 
spring? 

A.—Because one inch of height in the diagram 
represents the amount of pressure indicated on 
the spring, two inches the double, etc. 

Q* there a quick way of figuring the 

M. E. P.? 







l6o QUESTIONS AND ANSWERS 

A.—Yes. Make a rough sketch of a diagram 
and divide the length of it into io equal spaces; 
allow for the first four spaces (to cut-off) the full 
pressure as per gauge, say ioo lbs. each, divide 
their sum, 400, by 5, the number of the next space, 



allowing the quotient, 80, for the fifth space; 
then divide the same sum, 400, by 6 and allow 
this quotient for the sixth space, and so on, to 
the last space. Add all these figures together, 
and divide by 10 and proceed as above. (See 
cut.) 

Q.—Is this a very accurate way? 

A.—No, but it will answer for a rough figuring 
under ordinary circumstances. 

Q.—How is the pantograph used in connection 
with the indicator? 

A.—One end of it (C) is fixed to the crosshead, 

* 

the other (D) is made stationary by a fixed stake 













THE INDICATOR 


161 


placed in line with the crosshead socket at mid¬ 
stroke. A peg (F) is placed in one of the holes on the 
adjustable strip G, so as to be on the line between 



the two points C and D, and at such distance 
from C that the cord connecting it with the 
indicator drum will be parallel with the guides. 



The peg will not move as fast as the piston head, 
but it moves at exactly the same ratio, giving an 
accurate diagram. (See cuts.) 
















162 


questions and answers 


INDICATOR EXAMINATION 

Q.—Can any one use the indicator intelligently? 

A.—No, only one who has had experience with 
engines, who possesses power of observation, and 
who is familiar with measurements and calcula¬ 
tions. 

Q.—What length can a diagram be? 

A.—Five and one-fourth inches extreme length. 

Q.—What do the length and the height of the 
diagram represent? 

A.—The length represents the length of the 
stroke. The diagram is one inch high for every 
15 or 20, etc., lbs. pressure, according to the 
spring scale. 

Q.—If the 30 lbs. spring is used and the diagram 
is 2 l /% inches high, what does this indicate? 

A.—It would indicate that the greatest pressure 
during the stroke (steam line) was 2}£ times 30 
lbs. 

Q.—Would the 15 lbs. spring answer in this case? 

A.—No. The pressure would be 63^ lbs., 
while the 15 lbs. spring is not able to act under a 
pressure of more than 21 lbs. 

Q.—Explain the steam line? 

A.—It runs from the place of admission to begin¬ 
ning of cut-off. 

Q.—Where is the exhaust line? 


THE INDICATOR 163 

A.—It begins at the point of exhaust or release. 

Q.—Which is the expansion line? 

A.—It is the curved line between the cut-off and 
the point of exhaust. 

Q.—What is the vacuum line? 

A.—The straight line at the extreme narrow 
end of the diagram running from the atmospheric 
line to the exhaust line. 

Q.—Does this line indicate a real vacuum? 

A.—No, it indicates a reduction of the atmos¬ 
pheric pressure from 15 lbs. down to 3 lbs. 

Q.—What points does an indicator card show? 

A.—The high and low pressure, cut-off and lead, 
exhaust point and atmospheric point. 

Q.—How does the steam line show on a card 
when steam is wire drawn? 

A.—It falls as the piston advances. 

Q.—What is meant by wire drawing? 

A.—It is reducing the pressure by choking. 

Q.—When should the atmospheric line be taken 
on the card by indicator? 

A.—Immediately after the card has been taken. 

Q.—Why? 

A.—Because the spring in cooling will change 
the position of the pencil point. 

Q.—How is the atmospheric line drawn? 

A.—By holding the pencil lightly against the 
card, taking care not to get it out of its true posi¬ 
tion, and then revolving the drum with the hand, 


164 QUESTIONS AND ANSWERS 

Q.—What is an ordinate? 

A.—It is the length of a line showing the height 
of a point above a level or line. 

Q .—How many ordinates are marked on a 
diagram? 

A.—You may mark any number. The larger 
the number the more accurate will be the result. 
Ten is the number usually taken for ordinary 
purposes. 

Q.—Where do you place the ordinates? 

A.—In the middle of the ten equal spaces into 
which I divide the diagram. 

Q.—What does each single ordinate show? 

A.—It indicates the mean effective pressure 
during the time in which the pencil passes across 
the space, in the middle of which the ordinate 
lies. 

Q.—What is meant by “mean”? 

A.—If the pressure was 60 lbs. on entering a 
space and ran down evenly to 55 lbs. on leaving 
the space, 57^ lbs. would be the half-way between 
the two, or the “mean,” which may be safely 
called the pressure all across the space. 

Q.—After the card has been properly laid out, 
what should be done? 

A.—Measure the combined length of all the 
ordinates, divide their sum by the number of 
ordinates, and multiply the quotient by the 
figure on the spring scale in use. 


THE INDICATOR 


i 6 5 


Q.—How do you “add” the ordinates? 

A.—By laying them off in one continuous 
straight line on a cardboard, then measuring their 
total length in inches. 

Q.—Suppose the total length of the ten ordinates 
were 8 inches and the spring used was a 50 scale, 
how would you proceed? 

A.—The eight inches and 10 ordinates equals 
eight-tenths, or .8, multiplied by 50 scale equals 
40 pound average pressure in the cylinder of 
engine. 

Q.—Does the indicator allow for all friction, 
etc. ? 

A.—Yes. 

Q.—How are the ordinates measured, when the 
expansion line drops below the atmospheric 
line? 

A.—The sum of the lengths below the atmos¬ 
pheric line is subtracted from the sum of those 
above. Otherwise the calculation is the same. 

Q.—What does the scale number on an indicator 
card mean? 

A.—It indicates what pressure will lift the pencil 
point one inch. (See cut, page 156.) 

Q.—What is meant by mean effective pressure? 

A .—It means the average pressure of steam in 
the cylinder during one stroke. 


THE COMPRESSED NON-VIBRATING AIR 
OR STEAM ENGINE 


CAN BE USED TO PROPEL HORSELESS CARRIAGES, 
YACHTS, MOTOR WAGONS, ETC. 

The growing demand for a small engine, more 
particularly for traction and marine work, simple 
in construction and operation, economical, non¬ 
vibrating, light weight, yet strong and compact, 
and reversible by simply shifting the valves, has 
resulted in the perfection of an engine far in 
advance of anything heretofore made for the 
purpose. 

One of the more essential requirements for the 
above purposes is: Sufficient strength to start a 
given load from a standstill, which must be 
greater than the force necessary to overcome 
ordinary obstacles when in motion. 

The “compressed air engine” develops extreme 
power for its weight and the space it occupies. It 
also dispenses with all vibration, which heretofore 
has been the great trouble in locomotion of horse¬ 
less carriages, etc. 

Description: The cylinder, as seen in follow¬ 
ing cut, has 2 ports, 3 pistons, 1 stuffing box, 1 
crosshead and slide for same and connecting rods 
to a double crank arm shaft. No cylinder heads. 
This construction makes no difference in the 

166 



THE COMPRESSED NON-VIBRATING AIR OR STEAM 
ENGINE 


A A, Bedplate; B B, Double Cranks and Shafts; 
C C, Cylinder; D D, 3 pistons; E E, Center 
Piston Rod and Connecting Rod; F Fi F2 F3, 
Four Connecting Rods; I, Eccentric; J, Eccentric 
Rod; K, Engine Tube Frame. The steam chest 
does not show, being behind the cylinder. 

167 

































































































l68 NON-VIBRATING AIR OR STEAM ENGINE 

action, but it does in the results obtained. The 
two outside pistons are fastened together so as to 
move in the same direction, and are connected to 
one side of the crank shaft. The center piston, 
acting between these two, is connected centrally 
between two cranks and always moves in the 
opposite direction from the two outside pistons. 
It travels between the two ports, first meeting 
the lower piston at lower port, then reversing and 
meeting the upper piston at the upper port, the 
two outside pistons always traveling outside of the 
two ports, thus answering the purpose of the two 
cylinder heads, which are simply converted into 
movable heads or pistons. 

In a starting pull, the same charge of steam or 
air acting on both pistons at the same time gives 
twice the power at starting and a double expansion 
for the balance of the stroke. The ports and 
exhaust are the same in construction and opera¬ 
tion as standard makes of engines on the market. 

MENDING A BAND SAW 

Bevel both ends of the saw the length of two 
teeth. Fasten the saw in brazing - clamps, with 
the backs against the shoulders. Wet the joint 
with solder fluid (or with a lump of borax rubbed 
into a creamy paste with a teaspoonful of water on 
a slate). Put a piece of silver solder of the shape 
of joint in the joint, and clamp with tongs heated 
to a light red heat. As soon as the solder fuses, 
blacken the tongs with water (taking care not to 
get any water on the saw), release tongs and 
smooth the . joint by hammering and draw-filing. 



MISCELLANEOUS 

QUESTIONS AND ANSWERS 

ON THE ENGINE 

TRAVEL OF CRANK PIN AND CROSSHEAD 


Q.—Do crank pin and crosshead travel at an 
even gait during one revolution of the disc? 



the crosshead travels only a very short distance 
while the crank pin moves 15 degrees (*4 of 90°, a 
quarter revolution) upward from the dead center; 
(2) that the distance traveled by the crosshead 
increases in each of the 5 following spaces, each 
of them corresponding to the crank pin’s travel of 
15 degrees (6x15° = 90°); (3) that the crosshead has 
traveled more than one-half of its stroke (the half¬ 
way point is indicated by a dotted line in the cut), 
when the crank pin,has traveled 90°, or % revolu¬ 
tion. 


169 
























170 


MISCELLANEOUS 


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highest elevation (see Fig. 2 ), and by laying A C off on A B we find AC = AB4-BE. 




































During one stroke the crank pin moves from D to Di in a half-circle, and the cross¬ 
head moves an equal distance in a straight line, H Hi. Therefore, the crosshead moves the 
distance H A during the first half-stroke, and the distance A Hi during the second half¬ 
stroke. M indicates the point dividing the length of stroke in halves. 


QUESTIONS AND ANSWERS 


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171 


in the first quarter? 

A.—Of course, it does; but in the first quarter it moved away from the level, besides 

* 

the crosshead’s motion along the level, and in the second quarter it moves toward the level. 


172 


MISCELLANEOUS 


Q.—Is a heavy disc or a fly wheel of service in 
this connection? 

A.—Yes, it serves to make the speed in a revolu¬ 
tion more even, so that the shaft revolves steadily, 
while the unevenness of motion is put on the 
piston. 

Q.—What other purpose does a fly wheel serve? 

A.—It serves to overcome the dead centers, 
where the piston can neither push nor pull. 

Q.—Does a crosshead stand still at dead center 
points? 

A.—No. The crosshead center could stand still 
only if the crank pin moved around it as the 
center. The following cut shows how the reality 
differs from such a case. 



H, Hi are the positions of the crosshead pin 
center when the crank pin center is at D, Di. The 
circle shows the real movement of crank pin; the 
two curves indicate the circles in which the 
crank pin would have to travel as long as the 
crosshead stood still. 




QUESTIONS AND ANSWERS I 73 

The movement near the dead centers is com¬ 
paratively slow, but as the crank pin does not 
stand still at the dead center, but is moving either 
toward it or away from it, the crosshead, moving 
with it, does not stand still either. The dead 
center is an imaginary point, having no dimen¬ 
sions; thus it cannot be said that the crank pin 
center remains at the dead center point any time , 
or that it takes the crosshead any time to change 
its direction of stroke. 

Q.—Can you illustrate this fact? 

A.—Yes. The pendulum of a clock does not 
stand still at either end of its arc of oscillation. 
No time intervenes between the end of one year 
or month or hour and the beginning of the next. 

Q.—Do the connecting rod brasses wear the 
crank pin evenly all around? 

A.—No, in running “over” only one-half of the 
circumference of the crank pin is pushed and 
pulled, while in running under it is the other naif. 
(In the full page cut the half affected in running 
“under” is shaded; the half affected in running 
“over,” the direction indicated by the arrows, is 
not shaded.) 

Q.—Why are horizontal engines (stationary) 
generally run over and not under? 

A.—So the thrust will be downward upon the 
foundation rather than up against the caps of the 
boxes and the upper guides. 


174 


MISCELLANEOUS 


Q.—How much farther does the crank pin travel 
than the crosshead each revolution? 

A.—One-half farther. The crosshead moves 
twice the diameter of the disc (back and forth), 
while the crank pin travels around the circum¬ 
ference (= 3.1416 times the diameter); 3 is more 
than 2 by half. 

Q.—Does a crank pin have a tendency to flatten 
on one side, or on both sides, traveling in one 
direction? 

A.—Simply on one side. The push and pull of 
the rod is on one-half of the pin only, as the pin 
turns with the crank, wheel or disc. 

HEAT 

Q .—Is heat a substance? 

A.—No, it is one of the energies developed-in 
molecular action. 

Q.—What are molecules? 

A.—The smallest possible parts into which any 
substance can be divided without losing its 
chemical identity. 

Q.—What is meant by “absolute zero”? 

A.—The absolute cessation of molecular action. 

Q. —When heat is applied from outside to a 
substance, what are the effects? 

A.— The substance increases in temperature, 
changes its volume, and, at certain degrees of 
temperature, changes its form, (See page 180.) 


QUESTIONS AND ANSWERS ,175 

Q.—What is meant by “latent heat”? 

A.—In expanding, gases take heat from their 
surroundings. This amount of heat does not 
increase the temperature of the expanding gas, 
and is therefore not measurable by the ther¬ 
mometer. Any heat expended in this or a similar 
way, and not “sensible,” or “noticeable to the 
feeling^” is called latent heat. 

Q. —How is sensible heat measured? 

A. —By means of a thermometer. 

Q.—How is a thermometer constructed and 
graduated? 

A.—A glass tube with bulb at closed end is 
partly filled with mercury, and heated until the 
mercury overflows. Then the open end is closed 
by fusing, and when cooled, the bulb is placed in 
melting ice and the point to which the mercury 
falls is marked the freezing point, 32 deg. Then 
place it in boiling water which is exposed to the 
open air and when the mercury rises to its full 
height, mark it 212 deg., or boiling point. The 
distance between the two points is 180 deg. 

Q.—What causes the mercury to rise and fall? 

A,—Expansion and contraction. 

MEASUREMENTS AND CALCULATIONS 

Q.—Give a general rule for determining the 
sizes of piston rods for steam engines? 

A.—They should be 1-6 the diameter of the 
piston-head. 


176 


MISCELLANEOUS 


Q .—Does this rule answer for all-sized cylinders? 

A.—No; only sizes ranging from 4 inches up to 
28-inch cylinders. For sizes above 28 inches the 
piston rods are smaller in proportion. 

Q. —Suppose there were 2 pounds of steam in the 
cylinder, how much pressure would there be 
between the piston head face, valve face and 
cylinder head? Explain by rule? 

A.—Rule: First find the area of piston and 
multiply by pressure in cylinder. 

Q.—What is the meaning of the term ‘‘clear¬ 
ance” in an engine cylinder? 

A.—The unoccupied space between the valve 
face, cylinder head and piston head at each end 
of the stroke. 

Q.—Which end of the cylinder has the most 
power? 

A.—The end without the piston rod. 

Q.—Explain why so? 

A.—Because the steam has more square inches 
to act upon in the end without the piston rod. 

Q.—How would you know the safe pressure to 
carry in a boiler l / 2 inch steel, 42 inches diameter, 
and 50,000 lbs. tensile strength? 

A.—First multiply thickness of shell by full 
tensile strength and divide by half the diameter 
(radius), and divide by 6, which gives the safe 
pressure allowed by U. S. if welded. If boiler 
shell is double riveted multiply by .70 (= 70 per 


QUESTIONS AND ANSWERS 177 

cent), in single riveted multiply by .56 (= .56 per 
cent). 

Q.—What is understood by a unit? 

A.—The basis of measurements, such as the 
day for measurements of time; the dollar for 
money; the atmosphere (14.7 lbs. per sq. inch) 
for pressure; the caloric (heat required for 
raising temperature of one lb. of water one 
degree) for heating; the horse-power (33,000 lbs. 
raised one foot high) for energy; the volt for 
electromotive force, etc. 

Q.—What is a “thermal unit”? 

A.—The amount of heat found necessary to 
raise or lower a pound of water 1 degree (Fahr.) 
of temperature. 

Q.—What is meant by positive and negative 
heat? 

A.—The former means the work of actual heat¬ 
ing ; the latter means the work done in cooling. 

Q.—How is the weight of the atmosphere found? 

A.—By the barometer. 

Q.-t-How does it show? 

A.—Air, being a substance, has weight. The 
atmosphere surrounding the earth presses at sea 
level with an average weight of 14.7 lbs. per sq. 
inch. This atmospheric pressure balances a 
column of mercury, in the vacuum arm of a 
siphon, of about 30 inches height. As the air rises 
(when heated, as in summer over a sandy plain) 


i 7 8 


MISCELLANEOUS 


or sinks (when cold or heavy with moisture), we 
have lower or higher pressure and the barometer 
indicates this by the lower or higher position of 
the top of the mercury column in the vacuum tube. 
For better indication the scale is generally 
attached to the open arm, which is made very 
narrow so as to show greater differences. 

Q.—How much does the whole atmosphere 
weigh? 

A.—It is estimated at five trillions of tons, the 
weight of a solid leaden ball of 60 miles diameter. 

Q.—How large should the stack be in proportion 
to the area of the tubes or flues combined of a 
stationary boiler? 

A.—The stack should be about 25 per cent, or % 
larger in area to do good work. 

Q.—How many square feet of heating surface is 
generally allowed to 1 square foot of grate surface? 

A.—From 22.5 to 40 square feet. 

Q.—Suppose the area of a valve is known, how 
is the diameter found? 

A.—Divide the area by .7854 and extract square 
root—answer equals diameter. 

Q.—How is the radius (half diameter.) found 
when area is known? 

A.—Divide area by 3.1416 and extract square 
root—answer equals radius. 

Q.—How is the linear dimension of a square 
found from the area? 


QUESTIONS AND ANSWERS 179 

A.—It is its square root. (See page 239.) 

Q .—How much will 1 cubic inch of steam 
expand after its release from a boiler? 

A.—About 1728 times, or into 1 cubic foot. 

Q. —How large should the diameter of a pump 
cylinder (plunger) be to deliver 324 gallons of 
water per minute, traveling 100 piston speed? 

A.—Divide 324 by constant 4, equals 81; from 
this extract the square root—answer equals 9 
inches, diameter of plunger. 

Q.—What size should the steam cylinder be as 
compared with the pump cylinder? 

A.—One-third larger in diameter. In the case 
mentioned, it should be 12 inches. 

Q.— How much of the steam generated in a 
boiler is allowed for consumption in the engine? 

A.—One-half only. With the usual average of 
70 lbs. steam and the feed water at the temper¬ 
ature of ioo° F., each 15 square feet of heating 
surface of the boiler will evaporate 30 lbs. of water 
per hour. The engine should, therefore, consume 
only 15 lbs. of water per hour for every 15 square 
feet of boiler-heating surface. 

Q.—What if the boiler is not capable of gener¬ 
ating double the amount of steam consumed by 
the engine? 

A.—The boiler will be overworked, which 
means shortness of life, many repairs, a great 
waste of labor and fuel, and much annoyance. 


MECHANICAL REFRIGERATION AND 
ICE MAKING 


THE SCIENTIFIC PRINCIPLE 

It is a well known fact that metals expand or 
contract as they are heated or cooled. Many 
other substances have the same quality, and it is 
a scientific truth, applying to all substances ca¬ 
pable of expansion, that a change of volume 
implies either an absorption of heat from , or a 
loss of heat to , the surrounditigs. 

Different substances have their extremes of 
volume at different temperatures. It is by no 
means so, that any substance will keep decreas¬ 
ing in volume indefinitely as its temperature 
decreases, or that its volume will keep increasing 
with increasing heat. Water, for instance, 
occupies the smallest space at 39.2° F. (the 
temperature found at the bottom of deep lakes), 
and has its extreme expansion at 212.8° F. (when 
it boils, or, in other words, when it changes from 
the liquid condition to the gaseous). Below 39.2 c 
F. water expands with decreasing temperature 
(this is why ice floats and bursts pipes); and 

it cannot be heated beyond 212.8° F., except 
180 



REFRIGERATION AND ICE MAKING l8l 


in a closed vessel, which serves to compress the 
steam into a smaller volume. 

From the above it will be understood that 

Gases when compressed yield heat 
to, and when expanding absorb 
heat from, their surroundings. 

THE APPLICATION OF THE PRINCIPLE 

A gas which will rapidly increase its volume 
when surrounded by a very low temperature, 

taking the heat it needs for expansion from the 
surroundings, will, therefore, create around it a 
very cold region. 

Scientists have frozen water in a bottle placed 
in a fire. The bottle was wrapped in woollen rags 
soaked in ether or chloroform, which evaporate 
so rapidly that they draw heat enough from the 
water in the bottle to freeze it. 

Common air can be reduced to a liquid by the 
alternate application of enormous pressure and of 
cooling. Liquid air boils at 312 0 below o F., a tem¬ 
perature almost inconceivable. Undoubtedly, 
liquid air will become a mighty agent in the hand 
of man before long. (See page 223.) 

Such a gas is, also, anhydrous ammonia , which 
boils under ordinary atmospheric pressure at 
28.5° below zero F. By compressing it in strong 
steel tanks it is kept in a liquid condition, and is 


182 questions and answers 

sold that way. From this tank (drum) it passes as 
a gas (vapor), feeding into a pump, which com¬ 
presses it again. In this condition it enters the 
evaporating coils, in which it is allowed to 
expand rapidly. In this rapid expansion a con¬ 
sumption of heat is necessary, and the required 
heat is taken from the brine in which the coils 
are immersed. Then the expanded vapor is 
exhausted into a condensing tank, the evaporating 
coils receive a new charge of condensed vapor 
from the pump, and the operation is repeated. In 
this way the brine is kept at the desired low 
temperature. The brine cannot solidify (freeze) 
on account of the salt it holds in solution. 

Q.—What is mechanical refrigeration? 

A.—It is produced by the evaporation of a 
volatile liquid which boils at a low temperature, 
and which by means of evaporating coils, a con¬ 
denser and a gas compressor, is brought under 
the control of the operator. 

AMMONIA 

Q.—What does the name “ anhydrous ” ammonia 
mean? 

A.—“Anhydrous” means “free from water” or 
“dry.” 

Q.—What is ammonia, and where is it found? 

A.—It is a gas composed of i part of nitrogen 
and 3 parts hydrogen. It can be obtained from 


REFRIGERATION AND ICE MAKING 183 

the air, from sal-ammoniac, nitrogenous con¬ 
stituents of plants and animals by process of 
distillation. As a matter of fact, there are very 
few substances free from it. At present almost 
all the sal-ammoniac and ammonia liquors are 
prepared from ammoniacal liquid, a by-product 
obtained in the manufacture of coal gas and coke. 

Q.—What are the properties of ammonia? 

A.—Pure ammonia liquid is colorless, having 
a peculiar alkaline odor and caustic taste. It 
turns red litmus paper blue. Its boiling point 
depends on its purity, and is about 28^ deg. F. 
below zero at atmospheric pressure. The purer 
the liquid the lower its boiling point. Compared 
with water, its weight or specific gravity at 32 
deg. F. is about % of water, or 0.625. One cubic 
foot of liquid ammonia.weighs 39.73 lbs. , 1 gallon 
weighs 5.3 lbs. One pound of the liquid at 32 
deg. will occupy 21.017 cubic feet of space when 
evaporated at atmospheric pressure. The specific 
heat of ammonia gas (heat required to raise one 
unit of it one degree of temperature, as compared 
with the heat required for the same weight of 
water, =1.) is 0.50836. Its latent heat of evapora¬ 
tion, as determined by the highest authorities, is 
not far from 560 thermal units at 32 degrees. 

Q.—What is a “refrigerant”? 

A.—Anything that cools, such as ammonia 
known as anhydrous or dry ammonia. 


184 


QUESTIONS AND ANSWERS 


Q.—What is the ammonia condenser? 

A.—It is that part of the apparatus in which the 
gas is cooled and changed to a liquid. 

Q.—How is the water changed into ice? 

A.—By a system of evaporating coils in which 
the liquid ammonia is expanded into gas, thereby 
cooling the space around by absorption of the 
heat. 



Q.—At what degree does pure anhydrous 
ammonia boil? 


A.—At from 28^ to 40 deg. below zero. (See 
table of boiling points, page 210.) 

Q.—What advantage does this give? 

A.—Ammonia can be kept at its boiling point 
without any artificial heat, which is not possible 
with water. 

Q.—Is ammonia the most serviceable of all 
refrigerants? 

A.—Yes, it has many advantages over other 
refrigerants. 






ABSORPTION AND COMPRESSION METHODS 185 

Q.—Which standard is applied to the amount of 
ammonia consumed in producing cold, weight or 
volume? 

A—Weight. 

Q .—Is ammonia inflammable and explosive? 

A.—It is not inflammable, and is, therefore, not 
explosive in the sense in which gunpowder is 
explosive; but at any temperature above 28.5 
below zero F. it is expansive like dry steam, and 
is, therefore, dangerous. 

Q.—Has ammonia any corrosive effect on steel 
or iron? 

A.—No; but on brass it eals. 

Q. —Has it any effect when mixed with water 
on the machinery or piping? 

A.—No. _ 

ABSORPTION METHOD AND COMPRES¬ 
SION METHOD 

Q.—Can you describe the absorption method or 
system? 

A.—Yes, but it is very little used now. 

The gas, instead of being compressed by 
mechanical means, is obtained from a 26 per cent 
solution of ammonia in water, heated in a boiler 
or still, until the ammoniacal gas is driven off. 
This gas then goes through the cycle of operations 
as described, until, having done its work of 
refrigeration, it is conveyed into the absorber. 



i86 


QUESTIONS AND ANSWERS 


Here the gas is brought in contact with the water, 
called the mother liquid, from which it was 



originally extracted in the still, this water in the 
meantime having gone through an elaborate proc¬ 
ess of cooling. The cool mother liquid rapidly 
absorbs the gas and forms again a strong solution 








ABSORPTION AND COMPRESSION METHODS 187 

of ammonia. This solution is returned to the still 
by means of a pump and is ready again to go 
through the -same cycle (round) of operations. 

Q.—Name the parts of an absorption apparatus? 

A.—Generator, ammonia pump, absorber, con¬ 
densing tank, weak liquor tank, equalizer, freez¬ 
ing tank, cooling tank and receiver for ammonia. 

Q.—What is the absorption system based upon? 

A.—The chemical law which allows ammonia 
to boil into gas at 28.5 deg. below zero, while 
water is not affected until 212 deg. is reached. By 
this the ammonia and water are capable of being 
separated and made to perform continuous duty. 

Q.—Is the compression system based on the 
same difference? 

A.—No, because anhydrous ammonia is used in 
this system. (“Anhydrous” means without water.) 

Q .—Why is it called a compression system? 

A.—Because it consists of alternate compression 
and expansion of the refrigerant. 

Q.—What are the different operations in this 
system? 

A.—There are three, namely, 1st, compression 
of the gas; 2d, condensation of the gas and a 
withdrawal of the heat caused by compression; 
3d, expansion of the gas and absorption by it of 
the heat from the surrounding objects. 

Q.—Explain process of compression? 

A.—The refrigerating agent (anhydrous am- 


l88 QUESTIONS AND ANSWERS 

monia) is furnished in heavy iron drums and 
allowed to enter, through connecting coils, the 
induction pipe in the compression pump, from 
whence it is drawn into the cylinders, where it 
is compressed to a pressure varying from 125 to 
175 lbs. per sq. inch. This variation of pressure 
is regulated by the temperature of the condens¬ 
ing water. This compression produces, by a 
largely increased friction of the gas molecules 
(small particles), intense heat. 

Q.—Does the pump get hot? 

A.—Yes, cold water is kept flowing around it, 
to cool it. 

Q.—Explain process of condensation? 

A.—The compressed gas is then allowed to 
enter the system of pipes known as the condenser, 
over which cold water is kept constantly flowing 
(see cut, page 203). The cold water absorbs the 
heat generated in the process of compression. 
The gas is thus cooled in its flow through the 
great lengths of pipe, until it finally cools to below 
28.5° F., when it collects in the receiver as a liquid. 

Q.—Explain process of expansion? 

A.—The liquefied ammonia, through a siphon, 
now slowly enters the expansion or evaporating 
coils, which are brought in contact with, or in 
close proximity to the objects to be cooled. As it 
enters these coils the high pressure before men¬ 
tioned is reduced, and the ammonia immediately 


ABSORPTION AND COMPRESSION METHODS 189 

re-expands' into the gaseous condition, absorbing 
the heat necessary for this process from the pipes 
and through them from the surroundings. Wher¬ 
ever two bodies of different temperature are 
brought in contact, the hotter will impart its heat 
to the colder until the temperatures are equalized. 

Q.—After having thus accomplished its cooling 
work, where does the gas go? 

A.—It is returned to the compressor, there to 
again begin afresh the cycle of operations, namely, 
compression, condensation and expansion. 

Q.—Is there any loss of ammonia during each 
operation? 

A.—Yes, very small. 

Q.—How often can ammonia be used in the 
manner just described? 

A. —Times without number. 

Q.—What is absolutely necessary to render these 
three operations continuous? 

A.—Each separate part of the machine (appa¬ 
ratus) must be suitably connected. (See testing 
and charging.) 

Q.—State the main points as to all appliances 
and machinery about a refrigerating plant? 

A.—Good order and cleanliness should be prac¬ 
ticed, also pump and valve tightly packed. 

Q. —What gives the greatest trouble about an 
artificial ice plant? 

A.—Leakage. 


BRINE SYSTEM AND DIRECT EXPAN¬ 
SION SYSTEM 

Q.—In what different ways is refrigeration done? 

A.—For lesser degrees of cooling, as for brew¬ 
eries, living-rooms, etc., the brine system is 
sufficient, in which the brine after being cooled by 
the ammonia is pumped through the pipes. For 
very low temperature, as needed in cold storage, 
direct expansion is used, allowing the gas to 
expand in the pipes, which are placed in the cool¬ 
ing rooms. 

Q.—Which of the two systems is more expensive? 

A.—The direct expansion system, both because 
of the large amount of specially made pipe 
required, and because the whole plant must be in 
operation day and night, to supply liquid ammonia 
for expansion. 

Q.—What advantage has the brine system over 
the direct expansion in ordinary conditions? 

A.—Ordinary piping may be used, and the large 
body of brine suffices to maintain the temperature 
desired in the rooms for a considerable length of 
time by merely operating the brine circulating 
pump, it very frequently being only necessary to 
operate the compressor in the daytime to maintain 
the temperature during the entire twenty-four 
hours. 

Q.—Describe the process of circulation in the 
brine system? 


DIRECT EXPANSION SYSTEM 191 

A.—It is done by a special pump known as the 
brine circulating pump, which forces it through 
the pipes arranged in the rooms to be cooled, 
from which it returns to the re-cooling tank and 
is used continually over and over again. 

Q.—Is the brine circulation independent of the 
gas? 

A.—Yes. 

Q.—Where and when do they come in contact? 

A.—In the brine tank only. 

Q.—Explain how this is done? 

A.—The cold ammonia gas extracts the heat 
from the brine as it flows through the tank in the 
circulation pipes. 

Q.—Do the two circulating systems come any 
nearer than that just mentioned? 

A.—No. 

Q. — What is the brine tank in an ice-making 
plant? 

A.—It consists of one or more salt water tanks, 
in which the evaporating coils of pipe are sub¬ 
merged, and the liquid ammonia is allowed to 
expand within, where it assumes its original 
gaseous condition and in so doing absorbs the 
heat from the brine, lowering the temperature to 
any degree required. 

Q.—How is the brine tank arranged for making 
ice? 

A.—It is a covered tank with many openings to 



IQ2 























































































































































































































DIRECT EXPANSION SYSTEM 193 

admit galvanized sheet iron tanks to hold distilled 
water for freezing into blocks of clear ice. (See 
opposite page; for model ice plant, see page 10.) 

Q.—How long will it take the water in the 
galvanized tanks to freeze a cake of the usual size, 
11x22x45 inches? 

A.—It is according to the temperature of the 
brine. 

Q.—If the brine is cooled to 14 deg. above zero, 
how long would it take? 

A.—About 60 hours. 

Q.—Why does it take so long? 

A.—Ice is a bad conductor; the ice forming first 
on the six surfaces communicates the cold very 
slowly to the water within. 

Q.—Is it a good plan to freeze the water 
quickly? 

A.—No; if frozen too quickly it will not be 
transparent, but cloudy. 

Q.—What is meant by the agitator and its use? 

A.—It is a centrifugal (rotary) pump used for 
drawing the brine from the bottom of one end of 
the tank and discharging it in the other end at the 
top, thereby securing uniform freezing by con¬ 
tinual circulation of the bath. 

Q.—How is the ice cake taken from the mold? 

A.—By running hot water over the can and 
dumping it. (See cuts of Eclipse thawing ap« 
paratus, next page.) 




ECLIPSE AUTOMATIC THAWING APPARATUS 
AND CAN DUMP. 


194 


























































































WATER EXAMINATIONS 


195 


TABLE OF BRINE SOLUTIONS 
(Chloride of Sodium, Common Salt) 


Percentage of Salt 
by Weight. 

0 

1 

5 

10 

15 

20 

25 

Degrees by Salo- 
meter at 60® F. 

0 

4 

20 

40 

60 

80 

100 

Specific Gravity at 
60° F. 

1 

1 007 

1 037 

1 037 

1 115 

1 150 

1 191 

Weight of One 
Gallon. 

8 35 

8 4 

8 65 

8 95 

9 3 

9 6 

9 94 

Pounds of Salt in 
One Gallon. 

0 

0 084 

0 432 

0 895 

1 395 

1 92 

2 485 

Pounds of Water in 
One Gallon. 

8 35 

8 316 

8 218 

8 055 

7 905 

7 68 

7 455 

Pounds of Water in 
One Cubic Foot... 

62 4 

62 172 

61 465 

60 253 

59 134 

I 

57 408 

55 695 

Freezing Point in 
Degrees F. 

32 

31 8 

25 4 

L8 6 

112 2 

6 86 

1 00 


WATER EXAMINATIONS 

FOR HARD WATER, ETC. 

Particles suspended in the water may be detected 
by filling a tall glass cylinder and placing same 
on a clean piece of white paper and looking down 
through the water. All waters are known as 
hard or soft, and in many cases hard water may 
be made soft and the air and gases be expelled by 
boiling, in which case it is called temporary or 
removable hardness. If unaffected by boiling it 
is called permanent hardness, and nothing short 
of distillation or boiling into steam and condensing 
the vapor will remove the cause, 


















196 QUESTIONS AND ANSWERS 

Q.—What is it that makes water hard, and how 
much of it is present? 

A.—Eight grains of mineral matter (carbonate 
of lime, etc.) or more in a gallon of water make 
it hard. 

Q.—How is the quality of hardness particularly 
noticeable? 

A.—When soap is used, the harder the water, 
the less effect has the soap, because the mineral 
matter neutralizes so much of it. 

SIMPLE RULES FOR ASCERTAINING THE QUALITY OF 
SO-CALLED MINERAL WATERS 

Water which will turn blue litmus paper red 
before boiling, but not after boiling, is carbonated 
(contains carbonic acid). The blue color can be 
restored by warming. 

If it has a sickening odor, giving a black sedi¬ 
ment, acetate of lead, it is sulphurous (containing 
sulphureted hydrogen). 

If it gives blue settlings with yellow or red 
prussiate of potash by adding a few drops of 
hydrochloric acid, it is chalytate (carbonate of 
iron). 

If it restores blue color to litmus paper after 
boiling, it is alkaline. 

If it has none of the foregoing properties in a 
marked degree and leaves a large residue after 
boiling, it is saline water (containing salts). 



THE APPARATUS USED IN THE BRINE 
AND IN THE DIRECT EXPAN¬ 
SION SYSTEMS 


The induction or suction valve is shown closed. 
the piston being on its upward stroke. Surround¬ 
ing the upper portion of the valve stem is seen a 
coiled spring which raises the valve, holding it 
firmly upon its seat, as shown above and in sec¬ 
tional view of compressor, page 199. 

As the piston commences its downward stroke 
the pressure of the gas in chamber D opens the 

valve and the cylinder commences to fill. 

197 


THE 

PUMP VALVE 



































































































































198 


REFRIGERATION 


Below A in Fig. 1 is seen a small passageway 
connecting the gas inlet space on the right with a 
small chamber on its left formed by the ring B 
on the valve stem and the bore of the valve cage. 
This passage opens a little above the bottom of 
the chamber, and when the valve is fully opened 
the ring B covers the passage, and the gas in the 
lower portion of th'e chamber, unable to escape, 
forms an elastic cushion, which prevents any 
strain on the valve stem and holds the valve in 
perfect equilibrium. 

The downward stroke being complete, the 
incoming gas no longer presses open the valve 
and by the combined action of the spring and 
the imprisoned cushioning gas it is instantly 
seated. 

The discharge valve is side by side with the 
induction valve, and works in the opposite sense. 

The requirements of a good pump are: To 
instantly admit the gas to the cylinder, filling it 
full at each downward stroke of the piston; to 
expel (discharge) the entire contents of the pump 
through the outlet valve K, Fig. 2, which opens 
as soon as the cylinder pressure overcomes the 
combined force of the valve-spring and of the 
pressure in the condenser beyond the valve 

Valves, of ample area, durable in construction 
and reliable in action, must be supplied. A 
piston is required that is perfectly tight, yet 


J 


K 



IQ9 


Z2ZZ) 






























































































200 


THE APPARATUS 


working freely, and a stuffing box for the piston 
rod in which the packing can be readily adjusted 
while in operation. 

The stroke of the piston is accurately gauged 
so as to reach within a hair’s breadth of the upper 
cylinder head in order to force all the gas out. 

Just above the lowest position of the upper face 
of the piston head there is a ring of 8 openings in 
the cylinder wall, connecting with the induction 
chamber D. Through these holes, whose total 
area equals that of the induction valve, the gas 
enters at the lowest position of the piston head, 
thus securing a complete filling of the cylinder, 
after the induction valve has closed. For the 
induction valve, as shown by the indicator, admits 
only about three-fourths of the desired amount of 
pressure, because, with the spring tension, this is 
enough to balance the pressure in the induction 
chamber. 

As the piston rises again, it closes the ring of 8 
openings, until it passes beyond them, when the 
gas enters once more through them to fill the 
vacuum under the piston. In the downward 
stroke, when the piston closes these openings, the 
remaining gas under it is pressed through small 
openings (shown white in the cut) at the bottom 
of the cylinder into the closed chamber N, 
whence it issues again at the beginning of the 
upward stroke, working like a cushion. 


mm 



PURGING VALVE 


DISCHARGE 
STOP 1 VALVE 


VALVE 


.water: 


JACKET- 


PUMP 


WATER INLET 


AIR PLUG 


Packing 


GAS.'irJLET 


Packing 


AMMONIA COMPRESSION PUMP 


201 























































































































































































































202 


THE APPARATUS USED 


THE STUFFING OR PACKING BOX 

The leakage.of ammonia, even if so slight as to 
cause but little expense, is always an annoyance. 
Confined as it is in the pipe system, in endless 
coils without the possibility of escape, the only 
portions of the plant needing careful attention, to 
guard against leaks, are the stuffing boxes B, 
Fig. 2, of the compression pump piston rods A. 

The stuffing box is of unusual depth, but with 
whatever care it is designed, engineers are aware 
that frequent attention is required in all machines 
to keep the packing set up enough to prevent 
leakage, and still not so much as to induce heat¬ 
ing and the consequent cutting of the rods. 

The stuffing box is under perfect control of the 
engineer at all times. Its geared gland Ci, Fig. 
2, connects with a short rod F. Turning the 
handle F will tighten or loosen the packing. 
The engineer can regulate the pressure upon the 
packing while the pump is in motion. 

To guard against the leakage of ammonia, in 
addition to the very long stuffing box already 
mentioned, a lubricating chamber with oil pipe 
G is attached for lubricating the piston rod within 
the packing. 

THE AMMONIA CONDENSER 

The ammonia—leaving the compression pumps 
hot, compressed, but still gaseous—reaches the 
condenser, which consists wholly of piping and 


IN REFRIGERATION 


203 


should be conveniently located on the roof of the 
building. The condenser should be divided into 
two parts, namely, the preliminary condenser and 
the liquefier, as shown in the illustration on this 
page. 

The gas when discharged from the compressor 



AMMONIA LIQUEFIER 
WITH PRELIMINARY CONDENSER. 


passes into a trap where oil and other foreign 
matters are deposited; from the trap it passes into 
the preliminary condenser (3), which is located a 
little lower than the bottom of the liquefier. After 
being cooled to a considerable extent in the pre¬ 
liminary condenser the gas passes through another 
oil trap (1), which thoroughly eliminates even the 









204 


THE APPARATUS USED 


slightest trace of oil still remaining in the am¬ 
monia. When it is remembered that the ammonia 
supply ought to do its work for a long period of 
time in the performance of the never-ending 
cycle of operations, and that all foreign substances 
act injuriously on both gas and machinery, it is 
apparent that it is of the most vital importance to 
keep the gas absolutely free from all impurities. 
This the additional oil trap successfully accom¬ 
plishes. 

Thus, completely purified, the gas passes out to 
the liquefier (2), where it is cooled to a liquid. 

The condensing pipes are cooled by water. In 
the open air system the water drips on the top 
coils and from them down on the lower ones, until 
it reaches the shallow tank in which the prelimi¬ 
nary condensing coils are immersed. Thus the 
water is hottest when it meets the hottest gases. 
A waste pipe carries the overflow of hot water to 
the steam condenser. 

In another cooling system, the,condensing pipes 
are entirely submerged in a water tank, the 
water flowing in at the bottom and' running out 
near its surface. The work of condensing can, 
therefore, not be divided up as in the open air 
system. 

The divided form of condenser possesses marked 
advantages and is a great improvement over the 
old method of arrangement. The warmest water 


IN REFRIGERATION 


205 


meets the hottest gas, and, as it has already per¬ 
formed duty on the liquefier, it is used on the 
preliminary condenser, without expense. 

All the coils should be made from extra heavy 
special drawn pipe, bent cold, and finished coils, 
which should be tested under many times the 
pressure they will ever be subjected to in actual 
use. 

The liquid ammonia flows into the receiver, 
where it is ready to perform the work of cooling 
either by expanding into coils in tanks or by 
expanding into coils in rooms to be cooled. 

THE EXPANSION COILS 

The ammonia, which left the compression 
pumps and entered the condenser as a gas through 
a large pipe, now leaves the condenser in a pipe 
■from one-half to one inch in diameter, and enters 
the third division of the system, there again to 
expand into its original gaseous condition. And 
it is while expanding to this gaseous condition 
that the ammonia absorbs the heat from the sur¬ 
rounding objects ere it returns to the compressor 
to be again compressed. 


SOLDER AND SOLDERING FLUID 

Bar solder: 1 lb. block tin, * 41 b. lead. 

Glazing solder: 1 lb. block tin, 1 lb. lead. 
Plumbing solder: 1 lb. block tin, 2 lbs. lead. 

For a good soldering fluid, drop small zinc strips 
into 1 oz. of muriatic acid until the bubbles cease 
to rise, then add % teaspoonful of sal ammoniac. 



COLD STORAGE TEMPERATURES 


ARTICLES. 

0 Fahr. 

ARTICLES. 

® Fahr. 

Fruits. 


Canned Goods. 



32-36 

Sardines. . 

35-40 

Bananas. 

34 

Fruits (Nuts in shell). 

35-40 


36 

Meats. 

35-40 

Cranberries. 

33-36 



Cantaloupes. 

40 



Dates, Figs, etc. 

50-55 1 

Butter. Eggs, etc. 


Fruits, dried. 

35-40 


18 20 

Grapes. 

34 36 


18 20 

Lemons. 

33-36 

Cheese, Chestnuts. 

34 

Oranges. 

34-36 


31 

Peaches. 

34-36 i 


Pears, Watermelons . 

34-36 | 





Liquids. 


Meats. 


Beer, Ale, Porter, etc. 

33 

Brined. 

38 


30 

Beef, fresh. 

33 


36 

Beef’ dried. 

36 40 

Wines. 

40-45 

Calves. 

32 33 



Hams, Ribs, Shoulders 




(not brined). 

20 



Hogs. 

29-32 

Flour and Meal. 


Lard. 

38 

Buckwheat, — Wheat 


T.ivprs 

20-30 

Flour. 

36-40 

Sheep. Lambs. 

32 

Corn Meal, Oats. 

36-40 

Ox-tails. 

30 



Sausage Casings . 

20 



Tenderloins, Butts,etc. 

33 

Miscellaneous. 


Vegetables. 


Furs, Woolens, Cigars. 


Asparagus, Carrots ... 

34 35 

Honev. Maple Syrup, 

oD 

Cabbage, Celery. 

34-35 

Sugar. 

40-45 

Potatoes . 

36-40 

FT opS 

40 

Dried Beans, Corn, 


Oils. 

35 

Peas. 

32 40 

Poultry, dressed, iced. 

28-30 

Onions, Parsnips . 

34 35 

,, dry picked... 

26-28 



„ scalded . 

20 

Fish. 


Game — Poultry — to 


Fresh Fish. 

20 

freeze . 

15 18 

Dried Fish. 

36 

Game after frozen.... 

25-28 

Oysters in shell. 

30 35 



Oysters in tubs. 

‘25 

1 




206 


































































BYE PASS VALVE 


207 


AMMONIA VALVES AND FITTINGS 


1. Expansion valve. 

2 . Ninety-degree angle 

valve. 

3 . Cross valve. 

4 . Return bend. 

5 . Ammonia tank 

valve. 


6 . F orty-five-degree 

angle valve. 

7 . Coupling. 

8 . Joint cross. 

9. Liquid valve. 

10 . Ninety-degree angle 

purger valve. 

11 . Union loop. 




BYE PASS VALVE ON THE DOUBLE 
AMMONIA GAS PUMP 

Through the bye pass the ammonia can be 
readily exhausted from any part of the system and 
may be stored in any other part temporarily until 
the repairs or examinations are made. 

By the peculiar arrangement of pipes and 
valves the action of the compressor and pump can 






208 


BYE PASS VALVE 


be reversed and the gas pumped from the con¬ 
denser, storing it in the brine tank. 

In each case, after the examination of any 
part, the air can be exhausted therefrom and 
charge of ammonia reintroduced without the 
admixture of air. 



A. B, Ammonia Pumps. 
Ai, A2, Discharge Stop 
Valves. 

Bi,B 2 Suction Stop Values, 
i, 2 - 3> 4, 5. 6, Bye Pass 
Valves. 


M. D, Main Discharge 
Pipe 

M. S, Main Suction Pipe. 
7, 8, 9, Bye Pass Pipes, 
io, Plunger Valve. 


Description: A, B, compressor pumps; Ai, 
A2, main discharge stop-valves; Bi, B2, main 
suction stop-valves; 1 , 2, 3, 4, 5, 6, bye pass 
valves; M. D, main discharge pipe; M, S, main 
suction pipe; 7, 8, 9, bye pass pipes, 
flow to Operate: To exhaust gas from pump 

























































































































BYE PASS VALVE 


209 


B, all bye pass valves should be closed to begin 
with; close main stop-valve Bi, B 2 and A 2 ; open 
bye pass valves 2 and 3 ; then by running pump 
slowly the contents of pump B can be exhausted; 
then close valve 4 and remove bonnet. After 
closing bonnet, air can be removed in same way, 
previously shutting main stop-valve Ai and ex¬ 
pelling the air through purging valve on pump- 
head; close all bye pass valves when done and 
open main stop-valve. 

To exhaust pump A—Proceed in same manner, 
using the opposite set of valves. 

To equalize pressure between condenser and 
brine tanks—Open stop-valve Ai or A 2 and bye 
pass valves 1 and 2 , also 5 and 6 , thus forming 
passage direct from main discharge to main 
suction pipe. 

To exhaust condenser and store gas in brine 
tank—All valves closed to begin with. Open 
stop-valve Ai on pump A, bye pass valves 1 and 
4, opening communication to pump suction B; 
expel gas by opening bye pass valves 2 and 5 , 
thus discharging into main suction pipe. Run 
pumps slowly by using opposite set of valves 
(either pump may be used), the mode of operation 
being simply that one pump is used to exhaust 
the gas through the bye pass from the discharge, 
while the other forces it through the other half of 
bye pass into the suction pipe. 


BOILING POINT OF AMMONIA 


Pressure. 

Boiling Point 

° Fahr. 

Latent Heat. 

Pressure. 

Boiling Point 

Latent Heat. 

Absolute.! 

J Gauge, 

Absolute. 

j Gauge. 

10.69 

—4.01 

-40 

579.7 

58.00 

43.30 

28.9 

537.6 

11.00 

—3.70 

—39 

579.1 

59.41 

44.71 

30.0 

536.9 

12.31 

—2.39 

—35 

576.7 

60.00 

45.30 

30.6 

536.5 

13.00 

-1.70 

—32.7 

575.3 

61.50 

46.80 

32.0 

535.7 

14.13 

—0.57 

—30 

573.7 

62.00 

47.30 

32.3 

535.5 

14.70 

To .00 

—28.5 

572.3 

63.00 

48.30 

33.0 

535.0 

15.00 

-f0.30 

—27.8 

571.7 

64.00 

49.30 

33.7 

534.6 

16.17 

1.47 

—25 

570.7 

65.93 

51.23 

35.0 

533.8 

16.71 

2.01 

_22 

568.9 

67.00 

52.30 

35.8 

533.3 

17.00 

2.30 

— 21.8 

568.7 

69.00 

54.30 

37.2 

532.4 

18.45 

3.75 

—20 

567.7 

71.00 

56.30 

38.6 

531.5 

19.00 

4.30 

—18.9 

567.0 

73.00 

58.30 

40.0 

530.6 

20.99 

6.29 

-15 

564.6 

74.07 

59.37 

41.0 

530.0 

21.27 

6.57 

—13 

563.4 

75.00 

60.30 

41.5 

529.7 

22.10 

7.40 

—12 

562.8 

76.00 

61.30 

42.2 

529.2 

22.93 

8.23 

—11 

562.2 

78.00 

63.30 

43.4 

528.5 

23.77 

9.07 

—10 

561,6 

80.66 

65.96 

45.0 

527.5 

24.56 

9.86 

— 9 

561.0 

88.96 

74.26 

50.0 

524.3 

25.32 

10.62 

— 8 

560.4 

92.00 

77.30 

51.4 

523.4 

20.08 

11.38 

- 7 

559.8 

95.00 

80.30 

53.2 

522.3 

26.84 

12.14 

— 6 

559.2 

97.93 

83.23 

55.0 

521.1 

27.57 

12.87 

— 5 

558.5 

100.00 

85.30 

56.1 

520.4 

28.09 

13.39 

— 4 

557.9 

104.84 

90.14 

59.0 

518.6 

28.64 

13.94 

— 3 

557.3 

107.60 

92.90 

60.0 

517.9 

29.17 

14.47 

— 2 

556.7 

110.00 

95.30 

61.1 

517.2 

29.70 

15.06 

— 1 

556.1 

115.00 

100.30 

63.5 

515.7 

30.37 

15.67 

+ 0 zero) j 

555.5 

118.03 

103.33 

65.0 

515.3 

31.00 

16.30 

•4-1.4 | 

554.6 I 

119.70 

105.00 

66.0 

514.8 


210 



































A FEW TESTS FOR AMMONIA 


Ammonia liquid for use in refrigerating machines 
should be absolutely pure. It should be tested. 
The various tests to which it should be subjected 
are: For water, for specific gravity, for inflam¬ 
mable gases, and for boiling point. 

TEST FOR WATER 

As shown in the engraving, screw into the 
ammonia flask a piece of bent 14 -inch pipe, 
which will allow a small bottle to be placed so as 



to receive the discharge from it. This test bottle 
should be of thin glass with wide neck, so that 
quarter-inch pipe can pass readily into it, and of 
about 200 cubic centimeters capacity—equals i.6g 
gills or a 6 % ounce bottle. Put the wrench on the 
valve and tap it gently with a hammer. Fill the 
bottle about one-third full and throw sample out 





212 


AMMONIA TESTS 


in order to purge (clean) valve, pipe and bottle. 
Quickly wipe off the moisture that has accumu¬ 
lated on the pipe, replace the bottle and open 
valve gently, filling it about half-full. This last 
operation should not occupy more than one 
minute. Remove the bottle at once and insert in 
its neck a stopper with a vent hole for the escape 
of the gas. A rubber stopper with a glass tube 
is the best, but a rough wooden stopper loosely 
put in will answer the purpose. Procure a piece 
of solid iron that should not weigh less than 8 
lbs., pour a little water on this and place the bottle 
on the wet place. The ammonia will at once 
begin to boil and in warm weather will soon 
evaporate. If any residuum, pour it out gently, 
counting the drops carefully. Sixteen drops are 
about equal to one cubic centimeter, and if the 
sample taken amounted to ioo cubic centimeters, 
sixteen drops of residuum shows one per cent 
impurities (adulteration), and 20 drops per 
cent. 

Care is necessary in the drawing of the sample, 
as a very little moisture in the bottle, or in the 
pipe, or a brief exposure to the atmosphere will at 
once affect its purity. 

TEST FOR SPECIFIC GRAVITY 

The specific gravities of aqua ammonia by the 
Beaume scale are given in the following table. 


AMMONIA TESTS 


213 


By drawing off some of the liquid in the tall test 
tube generally provided by ice-machine builders, 
the Beaume hydrometer may be inserted and the 
specific gravity read upon the scale. If water is 
present, the liquid will show a density pro¬ 
portionate to the percentage of water present. 


TABLE OF SPECIFIC GRAVITIES AND PERCENTAGE 
OF AMMONIA (CARIUS) 


Degrees 

Beaume. 

Specific 

Gravity. 

Percent¬ 

age. 

Degrees 

Beaume. 

Specific 

Gravity. 

Percent¬ 

age. 

10 

1.000 

0. 

21 

.9271 

19.4 

11 

.9929 

1.8 

22 

.921 

21.4 

12 

.9859 

3.3 

23 

.915 

23.4 

13 

.979 

5. 

24 

.909 

25.3 

14 

.9722 

6.7 

25 

.9032 

27.7 

15 

. 9655 

8.4 

26* 

.*8974 

30.1 

16 

.9589 

10 . 

27 

.8917 

32.5 

17 

.9523 

11.9 

28 

.886 

35.2 

18 

.9459 

13.7 

29 

.8805 


19 

.9395 

15.5 

30 

.875 


20 

.9333 

17.4 





* Called by the trade 29 % per cent. 

Specific Gravity of pure anhydrous ammonia is .623 


TEST FOR INFLAMMABLE GASES 

Take a pail of water, submerge the bent pipe 
therein, open the valve on flask slightly and allow 
a small quantity of gas to flow into the water. If 
inflammable gases are present they will rise in 
bubbles to the surface of the water and may be 
removed by igniting the bubbles by means of a 
lighted match or candle. As water has a strong 
affinity for ammonia it will be readily absorbed, 


















214 TESTING REFRIGERATING MACHINERY 

while air or other gases will show only in the form 
of bubbles. 

TEST FOR BOILING POINT OF ANHYDROUS AMMONIA 

By inserting the special low temperature stand¬ 
ardized chemical thermometer into liquid drawn 
into the 6 ^ oz. test glass jar, readings can be 
obtained through the side of the jar without 
removing the instrument Hold the thermometer 
in such a position that only the bulb is immersed. 

This test will give you the boiling point of 
ammonia at atmospheric pressure and it is well 
to know that the state of the barometer affects 
the temperature of the boiling point. With the 
barometer at 29.92 inches the boiling point should 
not be above 28.6 deg. below zero and may be 
much lower, depending upon purity of sample. If 
the ammonia is impure the boiling point is raised 
in proportion. 

TESTING THE REFRIGERATING 
MACHINERY 

Pressure Test.— It is important before introduc¬ 
ing the charge of gas into the machine system to 
carefully test every part of the apparatus and make 
it thoroughly tight under at least 300 lbs. air pres¬ 
sure, which pressure may be obtained by working 
the ammonia compressor (pump) and allowing 
free air to flow into suction side of pump by open¬ 
ing special valves generally provided for the 



TESTING REFRIGERATING MACHINERY 215 

purpose, the entire system being thus filled with 
compressed air at the desired pressure. 

While this pressure is being maintained a search 
is instituted for leaks, every pipe, joint and square 
inch of surface being scrupulously noted. One 
method is to cover all surfaces with a thick lather 
of soap, leaks showing themselves by formation 
of soap bubbles. In the case of condenser and 
brine tank coils, the tanks are allowed to fill with 
water, the bubbles of air escaping through the 
water locating the leak. 

It is important that the apparatus be thoroughly 
tight, and, as a few joints are to be made when 
new plants are put in, it is necessary to go over 
the entire surface of the system to be sure. 

While the machine is engaged in pumping air 
into the system advantage should always be taken 
of this opportunity to purge (clean) the system of 
all dirt and moisture. To do this properly, 
valves are provided so the apparatus may be 
blown out by sections, removing valve covers 
(bonnets), loosening joints for this purpose, so 
that it is positively known that each pipe, valve 
and space is strictly clean and purged of all dirt 
and traces of moisture. 

A final test may then be had by pumping air 
pressure of 300 lbs. into the entire system and 
allowing the apparatus to stand for some hours, 
estimating the leakage, if any, by noting the 


2 16 TESTING REFRIGERATING MACHINERY 


degrees of pressure as shown by the pressure 
gauge connected to system. The air pressure will 
shrink somewhat at first, by reason of losing heat 
gained during compression by the pumps. As 
soon as the air parts with its heat and returns to 
its normal temperatur^, the gauge will come to a 
standstill and remain at a fixed point (depending 
upon the barometer and upon the temperature of 
the room), if the system is tight. Never charge a 
system until it is well cleansed, purged and 
absolutely tight. 


VACUUM TEST 

After having tested the system with a pressure 
of 300 lbs. of compressed air, the air must be 
exhausted from the entire system, by working the 
pumps and discharging the „ air through valves 
provided therefor (located generally on the pump 
domes). When the escape of air ceases and the 
compound or vacuum gauges show a full vacuum, 
it is well to close all outlets and allow the 
machinery and system to stand for some time, to 
test the capacity of the apparatus to withstand 
external pressure without leakage. In some cases 
it has been discovered that parts while tight from 
internal pressure, owing to loose particles lodging 
over leaks and acting as plugs to prevent escape, 
give way and disclose the leakage when sub¬ 
jected to an external pressure. 


INTRODUCING THE CHARGE OF 
AMMONIA 

Place the ammonia flask (tank) on small plat¬ 
form scales, in order to weigh the contents and 
know positively when flask is exhausted. Con¬ 
nect the flask to the charging valve, the gauge 
still showing a vacuum, close the expansion valve 
in main liquid pipe connecting receiver to brine 
tanks; then open valve on ammonia flask and 
allow the liquid to be exhausted into the system. 

The machinery may be run all this time at a 
slow speed, with both discharge and suction hand 
stop valves wide open. 

As one flask is exhausted, place another on the 
scales and continue until the liquid receiver is 
shown to be partly full by the glass gauge thereon. 
Then shut the charging valve and open and 
regulate the main expansion valve. The machine 
is then sufficiently charged to do work, as shown 
by the pressure gauges and gradual cooling of the 
brine and frosting of expansion pipe leading to 
brine tank coils. 

While the system is being charged water is 
allowed to flow on the condenser, and time dili¬ 
gently employed in searching further for leaks, 
which can readily be detected by sense of smell, 

each joint being again gone over. 

217 


2 l8 


QUESTIONS AND ANSWERS 


Q.—Why are the joints and whole system again 
gone over after having withstood the two tests, 
300 lbs. air pressure and lowest vacuum? 

A.—Because ammonia in itself is a great dis¬ 
solvent and eventually it will purge and scour the 
entire system clean to the metal surfaces. 

Q.—Where does the loose foreign matter go? 

A.—It is caught in the separators and inter¬ 
cepted provided for this purpose. 

Q.—Is ammonia a lubricant? 

A.—Yes, slightly. 

Q.—Has it any effect on iron or steel? 

A.—None whatever. 

Q.—Has it any effect on brass, copper, etc.? 

A.—Yes, it eats and corrodes them. 

AIR IN THE SYSTEM 

Q.—What causes air to get in the system? 

A.—Negligence in regulating the expansion 
valve, needlessly pumping a vacuum on the brine 
tank, leaky piston rods, also taking the apparatus 
apart and not expelling the air before the re- 
introduction of the anhydrous ammonia gas. 

Q.—How is the pressure of air in system in con¬ 
siderable quantity readily noticed? 

A.—By the intermittent action of the expansion 
valve and singing noise, rise of condensing pres¬ 
sure, loss of efficiency in the condenser, etc. 

Q.—What means are provided for the escape of 


DISCHARGING AMMONIA 


219 


the imprisoned air to restore the apparatus to its 
normal condition of pressure and efficiency? 

A.—The purging (cleaning) valves on the con¬ 
denser or the bye pass. (See description of bye 
pass on pumps, pages 208 and 209.) 

TAKING THE AMMONIA OUT OF THE APPARATUS 

Q.—How can ammonia be taken out of the sys¬ 
tem of an ice machine without losing any of it? 

A.—If the plant is of ordinary construction and 
of compression (liquefying gas by gas pump) 
design, connect the liquid receiver by its bottom 
connection to the empty shipping tank and 
allow the gas to flow into the tank, being sure to 
have 'the tank on a scale to weigh the quantity 
you put in. 

Do not allow more to be placed in the tank than 
was originally in it when shipped. In other 
words, the tank must not be filled with liquid to 
more than five-eighths of its cubic contents. 

This is one of the most dangerous pieces of 
work that a refrigerating engineer is called on to 
do, and on the first trial the chances are about 
even that he will burst the compressor, blow the 
receiving tank up and possibly blow his own head 
off. 

QUESTIONS AND ANSWERS IN REVIEW 

Q.—How is the compressor pump cylinder kept 
cool? 

A.—It is incased with a water jacket through 


220 


QUESTIONS AND ANSWERS 


which cold water is constantly circulated (see J, 
Fig. 2, page 199). 

Q.—What causes the heat in the pump? 

A.—The compression of the gas. 

Q.—What kind of oil should be used in the com¬ 
pressor, if used at all? 

A.—Oil generally known as “the perfection 
ammonia pump oil,” or the cold test “zero oil,” 
which is especially manufactured, and which 
stands a very low degree of cold without volatiliz¬ 
ing. Sometimes the best paraffine oil is used, 
and again a clear West Virginia crude oil. These 
oils when subjected to a low temperature should 
not freeze. 

Never inject oil directly into the compressor, 
and use sparingly in the stuffing box. 

Q.—What is an oil separator used for? 

A.—It is to eliminate the small quantity of oil 
from the ammonia gas in its passage from the 
compressor to the condenser. 

Q.—Is the ammonia gas, when exhausted, in¬ 
flammable? 

A.—Yes, sometimes, if the oil traps have not 
absorbed the oil which the gas carries off from the 
hot pump. 

Q.—Is ammonia dangerous to handle? 

A.—It is, because when condensed to a liquid 
it is under an enormous pressure, which may 
cause great destruction when suddenly released. 


IN REVIEW 


22 f 


Q.—What advantage has the bye pass valve? 

A.—By means of it the ammonia can be ex¬ 
hausted from any part of the machine that may 
need repairing. 

Q.—What is an ammonia receiver, and where 
is it placed? 

A.—It is a tank to store liquefied ammonia, 
and is placed between the condenser and expan¬ 
sion valve (see condenser). 

Q.—What do the pipes in a cold storage room 
with a very low temperature contain? 

A.—They contain ammonia gas. 

Q.—What do the pipes used in a hotel for cool¬ 
ing living rooms contain? 

A.—They contain brine. 

Q.—What does a gas need for expansion and 
how does it get what it needs? 

A.—It needs heat and takes it from the sur¬ 
roundings. 

Q.—But what, if the surroundings have no 
heat? 

A.—Heat means any degree of temperature. 
Taking heat from surroundings means lowering 
their temperature. Taking heat from cold sur¬ 
roundings means making them still colder. 

Q.—In which three forms does matter exist? 

A.—Solid, liquid and gaseous. 

Q.—Does iron exist in these three forms? 

A.—We can liquefy it by melting it in great 


222 


QUESTIONS AND ANSWERS 


heat, and it is affirmed that iron exists in gaseous 
form in the sun. 

Q.—How can this be known? 

A.—“Spectral analysis’’ reveals the fact. 

Q.—Why does ice float? 

A.—Because ice is lighter than water at any 
temperature. 

Q. —What makes it lighter? 

A.—Expansion. A pound of ice has more 
volume than a pound of water. 

Q.—What would happen, if ice were denser and 
therefore heavier than water at any temperature? 

A.—In severe winters the deepest lakes would 
freeze solid down to the bottom. 

Q.—Does ice keep on expanding, the colder it 
grows? 

A.—No, there is a point at which it begins to 
contract again. 

Q.—Why does it not keep the same volume? 

A.—Because change of temperature is impos¬ 
sible without change of volume. 

Q.—Is that a law of nature? 

A. —It is a truth established by sufficient obser¬ 
vation, that one never occurs without the other. 


A STEAM AND WATER-PIPE CEMENT 

that will set under water, is made of 2 lbs. ground 
Paris white, 5 lbs. ground lithage, ^ lb. fine yel¬ 
low ochre, 14 oz. hemp cut up small. Mix well 
with linseed oil to the consistence of putty ,and use 
at once. 



LIQUID AIR, THE COMING FORCE 


Water freezes at 32 0 above zero. Mercury in a 
thermometer freezes solid at 40-42 0 below zero. 
The alcohol in a spirit thermometer freezes at 200 
below. Air becomes a liquid at 312 0 below zero. 

Eight hundred cubic feet of free air are con¬ 
densed into one cubic foot of liquid air. One pint 
of liquid air weighs one pound, like water. 

By the aid of a 50-horse-power steam air pump 
ordinary air is compressed until it becomes red- 
hot. ** Then it is cooled in submerged pipes, and 
is further compressed until the pressure is regis¬ 
tered at thousands of pounds to the square inch. 
More cooling is done, and more pressure applied, 
until, finally, the air liquefies. It oozes through 
the steel of the pipe in the shape of a milky vapor 
and trickles down into the receptacle below. 

As there is a difference of 344 0 between the 
temperatures of ice and liquid air, it will be under¬ 
stood why liquid air boils furiously even when 
placed on a block of ice. 

A hand thrust into this liquid, in appearance 
like water, would be destroyed in 10 seconds, but 
if drawn out again instantly, the moisture of the 
skin freezing to ice would be protection enough. 
The feeling at touching the liquid is like that 
of iron at white-heat. 


223 


224 LIQUID AIR, THE COMING FORCE 


Like quicksilver, liquid air does not adhere. If 
poured over silk, it will leave no stain. 

When boiling, the vapor of liquid air, being 
nothing but highly-compressed air, sinks to the 
ground. 

If water is poured into liquid air it turns to ice 
instantly, and of such a low temperature that it 
will not melt near a red-hot stove for a long time. 

A stick of arc light carbon, heated to 2,000 
degrees above zero, thrust into liquid air, causes the 
oxygen in it to burn with a dazzling bright flame. 

A teaspoonful of liquid air in a closed vessel, if 
lighted, explodes with tremendous force, jarring 
the ground like an earthquake. 

The expansive power of liquid air is about 20 
times greater than that of steam. 

Ten years ago it cost about $2,000 to produce 1 
gallon of liquid air. To-day, so Prof. Chas. E. 
Tripler, of New York, states, it can be manu¬ 
factured at the cost of 3 or 4 cents a gallon, at the 
rate of 40 or 50 gallons a day. 

Some of the uses to which this uncanny sub¬ 
stance can be put are as follows: 

A steam engine horse-power is now figured at 
$36.00 a year expense; by the use of liquid air it 
should not be more than about $7.00. 

The resistance in electric wires is entirely over¬ 
come, if submerged in liquid air. The intense 
cold knits the molecules of metal so closely that 


LIQUID AIR AND HYDROGEN 225 

it becomes a perfect conductor, without any 
leakage. 

A pocket flask full of liquid air will furnish free 
air for submarine apparatus for hours. 

It furnishes a clean, dry cold, at any desired 
temperature, for refrigerators, hospitals, engine 
rooms, etc. 

If used in propelling steamships, there would be 
no heat in the furnace room, and little need of a 
furnace. 

Guns using liquid air as an explosive would 
never get hot. 

Liquid air sprayed on dangerous wounds arrests 
blood poisoning instantly, as by a miracle. Malig¬ 
nant cancers have been cured by one drop of the 
liquid. All pulmonary and throat diseases, hay 
fever, asthma, diphtheria, grip and all fevers 
yield to a spray of liquid air. 

LIQUID HYDROGEN 

In the spring of 1898, Prof. Dewar, of the British 
Royal Institution, succeeded in liquefying the 
most volatile of all gases, hydrogen. Liquid 
hydrogen' is colorless, transparent, and of only 
one-fourteenth of the density of water. It is so 
cold that it freezes and solidifies air and oxygen 
instantly. In a closed tube brought in contact 
with it, the air freezes into a small lump, leaving 
the tube a vacuum. 


SCRATCH C AUCE. 


THE MACHINE SHOP 


226 























































SURFACE GAUGE. 


















































THE MACHINE SHOP 


One of the things by which a mechanic is 
known, is the way he keeps his tools. It makes 
no difference whether he works in a small shop or 
in one of the great establishments, every 
mechanic should be inflexible in following these 


two rules: 

1. Every tool should have its exact place, and 
should be in that place when not in actual use. 

2. Every tool should be in good order and ready 
for use. 

A mechanic with whom the constant observation 
of these rules has grown to be a habit, is worth 
three others to his employer, and saves himself a 
great amount of annoyance, loss and worry. 


LATHE GEARING 



To gear a lathe to cut any number of threads 
when no gear plate is attached to lathe head 

228 








THE MACHINE SHOP 


229 


block, simply find the run of gears belonging 
to the lathe to know if odd or even number of 
teeth are on gears. 

Multiply the number of threads to be cut to the 
inch by any small number from 3 up to 6 that will 
bring the answer even wiih one of the gears on 
hand. Say 10 threads are to be cut—4 times 10 
equals 40. Place this gear on lead screw of lathe. 
Multiply the same number (4) by the number of 
threads per inch on your lead screw, say 6. 6x4= 
24. Place 24 tooth gear on spindle, and connect 
by suitable intermediate. 

TURNING A BAU- 

There are expensive machines for turning balls, 
but common lathes will produce perfect spheres. 

Turn the piece first on centers, using the 
calipers to get it approximately near the shape; 
then cut off the centers. 

Make a cup in a chuckblock of hardwood, to 
hold a small section of the ball, and for the 
center use a blunt wood center with a concave 
piece of copper. Put the work in the chuck so 
as to take the first cut around it in the direction 
of its former centers, or axis. 

Cut lightly and a very narrow ribbon all 
around; then change the chuck so as to cut the 
second ribbon at right angles with the first, with 
the same depth of cutting. Then the third 


230 


THE MACHINE SHOP 


LATHE TOOLS 




1. Half Diamond Point. 

2. Diamond Point for 

steel and iron, left 
hand. 

3. Diamond Point for 

steel andiron, right 
hand. 

4. Heavy Diamond 

Point for Cast Iron. 

5. Right Side Tool, 

bent. 

6. Left Side Tool, bent. 

7. Right Side Tool. 


8. Left Side Tool. 

9. Inside Thread Tool. 

10. Inside Turning (Bor¬ 

ing) Tool. 

11. Bent Thread Tool. 

12. Thread Tool, 

straight. 

13. Roughing Tool. 

14. Cutting-off Tool. 

15. Water Finishing 

Tool. 

16. Round Nose Tool. 


Note: Set the cutting edge a little above the 
axis, or it will not cut properly, and may be drawn 
under and broken off. 


TWIST DRILL GRINDING 


231 


ribbon half-way between the first two, and so on, 
until the whole surface is covered. The right 
angle need not be measured except with the eye. 
Finish the ball with a hand tool, or scraper. 


TWIST DRILL GRINDING 

The cutting edges of a drill must have a 
proper and uniform angle with the longitudinal 
axis of the drill (Fig. 1); the two edges must be 
straight and exactly of the same length; and 
the lips must be sufficiently backed off (Fig. 6). 

Q.—What is the 
proper angle to 
which a drill should 
be ground? 

A.—59 degrees. 

(See Fig. 1.) 

* Q* — What is the 
result of an improper 
angle? 

A.—A lesser angle 
gives a longer edge, 
likely to hook and to produce a crooked and irregu¬ 
lar hole. A larger angle gives too short an edge 
to do the work easily. 

Q.—Where is the longitudinal axis of the drill? 

A.—It is at the intersection of the two longitu- 


59 







232 


QUESTIONS AND ANSWERS 


dinal planes indicated by the scribing (center line) 
along the middle of the two grooves. 

Q.—Of what importance is this axis? 

A.—The cutting edges must be at equal dis¬ 
tances from it, and also at the right distance to 
get the proper angle of point. 

Q.—What is this point? 

A.—It is the part where the two edges of the 
lips are run together in the center. If the cutting 
edges are too far from the axis the angle point 
does not cut; if too near, it cuts too rank. 

® 

Fig. 4 


Fig. 6 

T ig. 2 snows the proper proportions. In Fig. 3 
the edge is too near the center line, and in Fig. 4 
it is too far from it. 

Q. —What is clearance? 



Fig- 2 Fig. 3 












THE MACHINE SHOP 


233 


A.—The amount which is champered off back 
from the cutting edge. 

Fig. 5 shows how the clearance is determined 
as well as the height of the cutting lips, which 
should be equal, as stated before. 

Q.—What, if there is not sufficient clearance? 

A.—The drill will not cut, and under force will 
split or break. Fig. 6 shows the rear of lip removed. 

Q.—How would you start a drill? 

A.—By hand, in order to see first how it works. 
If it cuts well, the chips will show a clean cutting 
surface. 

Q.—Does a good drill in the machine cut small 
chips? 

A.—In cast metal, yes; but in wrought metal, 
it will cut a curled shaving sometimes very long. 

Q.—Why are the two grooves shallower near 
the shank than near the point? 

A.—The center is made thicker toward the 
shank for strength. As the drill wears short, the 
center must be thinned out by grinding, care 
being taken to remove an equal amount of stock 
on each side and so keep the point central. 

POLYGONAL NUTS 

A 4 sided nut is called square. 

A 5 “ “ “ “ a Pentagon 

A 6 “ “ “ “ “ Hexagon. 

A 7 “ “ “ “ “ Heptagon. 

An 8 “ “ “ “ an Octagon. 


RULES AND STANDARD NUMBERS 


DIAMETER, CIRCUMFERENCE AND AREA 

In a circle of one inch diameter describe 16 
radii at equal distances (Fig. i). The spaces 



between them and the 16 parts of the circum¬ 
ference may be arranged in a double row (Fig. 2). 

The circle area is thus divided up into 16 parts, 
8 of which are placed in nearly a straight line on 
each side of the row. 

By actual measurement the width of this row is 
% inch and the length 1.5708" (allowing a trifle 
for the difference between the 8 little curves and 
a straight line). 


Therefore cir¬ 
cumference 


=2 X 1.5708" 


= 3.1416" 


Area =1.5708" X 54" = 0.7854 sq. inch. 

Difference of) 

areas of circle >= sum of 4 corners (Fig. 1) = 0.2146 sq. inch 
and square ) 


^34 













RULES AND STANDARD NUMBERS 235 
STANDARD MULTIPLIERS 

1. For the area of a circle, multiply 

square of diameter by..7854 

2. For the circumference of a circle, mul¬ 

tiply diameter by.3.1416 

3. For the diameter of a circle, multiply 

circumference by.31831 

4. For the surface of a ball, multiply 

square of diameter by.3.1416 

5. For the cubic inches in ball, multiply 

cube of diameter by.5236 

6. For the cubic contents of a cylinder, 

multiply the area by the length. 

7. For the pressure in lbs..per sq. inch 

in a column of water, multiply its 
height in feet by.434 


AREA OF CIRCLES 


Diam. 

Area 

Diam. 

Area 

Diam. 

J Area 

Diam. 

Area 

H 

0.6013 

13 

132.73 

36 

1017.8 

71 

3959-2 

1 

0.7854 

14 

153-93 

37 

IO75.2 

72 

4071.5 

X 

1.767 

I4X 

165.13 

4 i 

1320.2 

76 

4536.4 

2 

3141 

I 6 < X 

205.97 

45 

1590.4 

80 

5026.5 

X 

3-976 

18 

254.46 

46 

1661.9 

8l 

5153-0 

X 

4.908 

X 

268.80 

47 

1734-9 

82 

5281.0 

X 

5-939 

19 

283.52 

48 

1809.5 

83 

5410.6 

3 

7.068 

X 

298.64 

49 

1885.7 

84 

5541-7 

X 

1 8.295 

20 

314.16 

50 

I963-5 

85 

5674-5 

X 

9.621 

X 

330.06 

5 i 

2042.8 

86 

5808.8 

8 A 

II.044 

21 

346.36 

52 

2123.7 

87 

5944-6 

4 

12.566 

X 

363-05 

53 

2206.1 

88 

6082.1 

X 

15.904 

22 

380.13 

54 

2290.2 

89 

6221.1 

5 

I9-635 

y 2 

397.60 

55 

2375-8 

90 

6361.7 


Q.—What difference is there between 3 square 


feet and 3 feet square? 


































2 3 6 


QUESTIONS AND ANSWERS 


A.—The first means 3 squares, each one foot 
square; the second is 9 squares, each one foot 
square, arranged in 3 rows of 3 squares each. 

Q.—Is there any difference between, one square 
foot and one foot square? * 

A.—No. 


WEIGHTS AND MEASURES 

Q.—How many square inches in a square foot? 

A.—12 times 12, or 144. 

Q.—How many cubic inches in a cubic foot? 

A.—12 times 12 times 12, or 1728. 

Q.—How many cubic inches in a gallon, in a 
cubic foot, in a bushel? 

A.—231 in a gallon; 1,728 in a cubic foot; 2,150 
in a bushel. 

Q.—How many gallons in a cubic foot of water? 

A.—7^4 gallons. 

Q.—How many cubic inches in one pound of 
water at 6o° F.? 

A.—27.71 cubic inches. 

Q.—How do you figure the gallons contained in 
a barrel? 

A.—Add together the two diameters (in inches) 
of the barrel at head and bung, and divide the 
sum by 2, which gives the mean diameter. Multi¬ 
ply the square of this diameter by .7854, which 
gives the area of the mean diameter circle in sq. 
inches. Multiply this area by the length of the 



WEIGHTS AND MEASURES 


237 


barrel in inches, to get the cubic contents in cubic 
inches, and divide the product by 231 to get the 
gallons. 

Example: A barrel 40 inches long, 19 inches 
diameter at the head, 25 inches diameter at the 
bung. 

19 + 25 = 44 44 - 5 - 2 = 22 

22 X 22 = 484 484 X .7854 = 380 

380 X 40 = 15200 15200 231 = 65.9 gals 

Q.—How much does a cubic inch of water 
weigh? 

A.—It weighs .0361 of a pound, or .577 of an 
ounce. 

Q.—What is the weight of a gallon, a cubic foot 
of water? 

A.—A gallon weighs 8 '/$ lbs., a cubic foot 62^ 

. lbs. 

Q.—What is the weight of a column of water, 
one inch sq. and 2.309 feet high, the temperature 
at 6o° F.? 

A.—One pound. 

Q.—What is the weight of a column of water, 
one inch sq. and one foot high? 

A.—It weighs .434 lbs. 

Q.—How much does a cubic inch of mercury 
weigh? 

A.—It weighs .49 of a pound. 

Q.—How much does a column of mercury one 
inch sq. and 30 inches high, weigh? 

A.—14.7 lbs. 


23 8 


QUESTIONS AND ANSWERS 


Q.—What is meant by a miner's inch? 

A.—It is approximately equal to a supply of 
12 gallons per minute. 

Q.—In what relation does the friction of water 
in pipes stand to the velocity of flow? 

A.—It increases with the square of velocity. 
If the velocity increases 4 times, the friction 
increases 16 times. 

Q.—In what relation does the capacity of pipes 
stand to their diameter? 

A.—It increases with its square. Doubling the 
diameter increases the capacity four times. 

Q.—How much water is consumed in obtaining 
one nominal horse power in heating buildings, etc. ? 

A.—One cubic foot. 

Q.—How much for engine purposes? 

A.—One-half cubic foot. 

Q.—How much heating surface is allowed for 
one nominal H. P. in boilers? 

A.—15 sq. feet for horizontal, and 12 sq. feet 
for vertical. 

Q .—How do you find the H. P. required to 
elevate water to a given height? 

A.—Multiply the total weight of water in lbs. 
with the height in feet and divide the product by 
33,000. Then allow 25 per cent for water friction 
and 25 per cent for steam loss, in all 50 per cent, 
or one-half, which is the same as dividing by 
♦ 16,500 instead of by 33,000. 


WEIGHTS AND MEASURES 


239 


Q.—How do you find the total amount of pres¬ 
sure exerted by a pump, and how the resistance? 

A.—The area of the sleam piston, multiplied 
by the steam pressure, gives the pressure. The 
area of the water piston, multiplied by the water 
pressure per sq. in., gives the resistance. 

Q.—If pressure and resistance are the same, 
does the pump work? 

A.—No, there must be a margin of from 30 to 
50 per cent steam pressure according to the re¬ 
quired speed. 

PULLEY SPEED CALCULATION 

Driven pulley revolutions are found by multiply¬ 
ing the diameter of the driver by its number of 
revolutions and dividing by the diameter of the 
driven. 

Diameter of driving pulley is found by multiply¬ 
ing the diameter of the driven by the number of 
revolutions it shall make and dividing the answer 
by revolutions of driver per minute. 

Diameter of driven pulley that should make a 
certain number of revolutions is found by multiply¬ 
ing the diameter of the driver by its number of 
revolutions and dividing by the revolutions the 
driven should make. 

SQUARE ROOT 

Q.—How is the square root of a number found? 

A.—1 st—Separate the number into periods of 


240 


WEIGHTS AND MEASURES 


two figures each, beginning at the right hand or 
digit space. 

2d—Find the greatest number whose square is 
contained in the period on the left; this will be 
the first figure in the root. 

3d—Subtract the square of this figure from the 
period on the left, and to the remainder annex 
the next period of two figures to form a dividend. 

4th—Divide this dividend, leaving out the last 
single figure on the right, by double the part of 
root already found, annex the answer to that part 
and also to the divisor, then multiply the divisor 
thus completed by the figure of the root last 
obtained and subtract the product from the 
dividend. 

5th—If there are any more periods to be brought 
down continue the operation in the same manner 
as before. 

Note—If a cipher occurs in the root, annex a 
cipher to the trial divisor and another to the 
dividend, and proceed as before. 


examples: 


18,66,24 I 432 Sq. Root. 


.0,00,36 I .006 Sq. Root. 


0 


83 I 266 
249 


00 | 00 
00 


862 | 1724 
1724 


006 | 0036 
0036 



LEVERAGE 


Q.—Name the different kinds of levers/ 

A.—Force, weight and fulcrum. 

Q.—If the fulcrum is between the force and 
weight, what kind of a lever would it be? 

A.—A lever of the first kind. 

Q.—If the weight is between the force and the 
fulcrum, what kind would it be? 

A.—A lever of the second kind. 

Q.—When the force is between the weight and 
the fulcrum, what kind would it be? 

A.—It is a lever of the third kind. 

Q.—State how the proportions of a lever of the 
first kind are found? 

A.—By dividing the length of that end of the 
lever between fulcrum and weight into the length 
of the opposite end. Example: If length of lever 
between fulcrum and weight is 6 inches and the 
other 18 inches the lever is said to be 3 to i, and 
a weight equal to 3 times the force applied at 
force may be lifted at weight by pulling down at 
force. 

Q.—How do you figure the lever of the second 
kind? 

A.—By dividing the length of the end of lever 
between the fulprujn and weight into the total 


242 


USEFUL KNOWLEDGE 


length of the lever. Example: If length of lever 
between fulcrum and weight is 6 inches and the 
other 24 inches the lever is said to be 4 to 1, and 
a weight may be lifted at weight equal to 4 times 
the force applied. 

Q .—What are the lever proportions of third 
kind? 

A.—They are found by dividing total length of 
lever into the length of the end between fulcrum 
and force. Example: If total length of lever is 
30 inches and the length between weight and force 
24 inches, the lever is said to be an 8-10 to 1. and 
a weight equal to 8-10 of the force applied at 
force may be lifted at weight. 


GENERAL USEFUL KNOWLEDGE 

AIR PURIFIER FOR ENGINE ROOM AND MACHINE SHOP 

The contrivance consists of a tubular casing 
adapted for insertion in a circular opening in the 
roof of a building or the deck of a vessel. Inside 
of the casing a sleeve is so supported as to leave 
an air-passage between the casing and the sleeve. 
Mounted in the sleeve is a tube provided internally 
with a spider or frame, and at its upper end with a 
rotatable ingress tube. This ingress tube likewise 
has a spider or frame on which a rod is centrally 
pivoted. The upper end of the casing is inclosed 


USEFUL KNOWLEDGE 


243 


by a hood formed with a conical end, through 
which the ingress tube passes. With the conical 
end of the hood an ingress tube 
is connected which communi¬ 
cates with the interior of the 
hood. These ingress and egress 
tubes are curved in opposite 
directions, and are mounted to 
swing in such a manner that the 
ingress tube shall constantly 
present its opening to the wind. 

The ingress tube continually forces a column of 
air downward through the building, and the egress 
tube permits all warm or vitiated air to escape. 
Any vacuum formed by ventilation, it is said, 
will be immediately filled by the air pressed into 
the cold tube entering a room at the bottom. The 
ventilator at the rear or leeward of the hood con¬ 
stitutes an air-passage, creating a vacuum below 
and drawing up the warm air. 



HOW TO READ A GAS METER 

The right hand dial of the three used for actual 
measurement, records the number of feet by 
hundreds, up to 1,000, the center dial the number 
of thousands up to 10,000, and the left hand one 
the number in tens of thousands up to 100,000. 
Thus, if the hands have passed the 5, 6 and 7 
figures on these dials the amount consumed is 
76,500, etc. 







THERMOMETERS 


Comparative 

Scales. 


Reau¬ 
mur, 
80-. 

Centi¬ 

grade, 

100°. 

Fahr¬ 

enheit 

212°. 

76 

95 

203 

72 

90 

194 

68 

85 

185 

63.1 

78.9 

174 

60 

75 

167 

56 

70 

158 

52 

65 

149 

48 

60 

140 

44 

55 

13! 

42.2 

52.8 

127 

40 

50 

122 

36 

45 

113 

33.8 

42.2 

108 

32 

40 

104 

29.3 

36.7 

98 

28 

35 

95 

25.8 

32.2 

90 

24 

30 

86 

21.3 

26.7 

80 

20 

25 

77 

16 

20 

68 

12.4 

15.3 

60 

10.2 

12.8 

55 

8 

10 

50 

5.8 

7.2 

45 

4 

5 

41 

1.3 

1.7 

35 

0 

0 

32 

— 0.9 

— 1.1 

30 

— 4 

— 5 

23 

— 5.3 

— 6.7 

20 

— 8 

—10 

14 

— 9.8 

—12.2 

10 

—12 

—15 

5 

—14.2 

—17.8 

0 

—16 

—20 

— 4 

—20 

—25 

— 13 

—24 

—30 

—22 

—28 

—35 

—31 

—32 

—40 

-40 


Rules for Conversion. 


Abbreviations: F. = Fahrenheit, C = 
Centigrade, R. = Reaumur 


To Convert 

F. to C., subtract 32 and multiply 
remainder by §. 

F. toR., subtract 32 and multiply 
remainder by 9. 

C. to F., multiply by § and add 32. 
R. to F., multiply by 4 and add 32. 
C. to R., multiply by 5. 

R.toC., multiply by f : 


244 





















USEFUL KNOWLEDGE 


245 


STOPPING WITH A HEAVY FIRE 

When it becomes necessary to stop an engine 
with a heavy fire in the furnace, place a layer of 
fresh coal on the fire, shut the damper and start 
the injector or pump for the purpose of keeping up 
the circulation in the boiler. 

TO PREVENT ACCIDENT BY THE SHAFTING 

While the shafts are in motion, it is strictly pro¬ 
hibited: a. To approach them with waste 

or rags, in order to clean them. b. To climb upon 
a ladder or other convenience in order to clean a 
shaft. 

These parts of the machinery must be cleaned 
by means of a long-handled brush only, and while 
standing upon the floor. 

The workmen charged with these or other func¬ 
tions about the shafting must wear jackets with 
tight sleeves, and closely buttoned up; they must 
wear neither aprons nor neckties with loose ends. 

Driving pulleys, couplings and bearings are to 
be cleaned only when at rest. 

This labor should, in general, be performed 
only after the close of the day’s work. If per¬ 
formed during the time of an accidental idleness 
of the machinery, or during the time of rest, or in 
the morning before the commencement of work, 
the engineer in charge is to be informed. 


246 


USEFUL KNOWLEDGE 


GRAPHITE IN STEAM-FITTING 

The value of graphite in making joints cannot 
be overestimated. Indestructible under all changes 
of temperature, a perfect lubricant and an anti- 
incrustator, any joint can be made up perfectly 
tight with it and can be taken apart years after as 
easily as put together. Rubber or metal gaskets, 
when previously smeared with it, will last almost 
any length of time, and will leave the surface 
perfectly clean and bright. Few engineers put to 
sea without a good supply of this valuable mineral, 
while it seems to be almost overlooked on shore. 

HOW TO OVERCOME VIBRATION 

How to put the smith shop in an upper story 
without having the working on the anvils jar the 
building, has been a problem that has frequently 
given manufacturers trouble. A mechanical 
engineer says it may be safely done by placing 
a good heavy foundation of sheet lead on the 
floor, and on that putting a good thickness of 
rubber belting. 

Another person who is interested in the problem 
has tried the experiment, with some success, of 
placing the block, not on the floor, but on the joist 
direct, making a cement floor up to the block, and 
over the wooden floor, reaching back beyond the 
reach of sparks. It is sometimes said that black¬ 
smith shops never burn, but they keep right on 


USEFUL KNOWLEDGE 


247 


burning in spite of theory, and cement floors 
ought to be helpful in guarding against fires. 

STEAM AS A CLEANSING AGENT 
For cleaning greasy machinery nothing can be 
found that is more useful than steam. A steam 
hose attached to the boiler can be made to do 
better work in a few minutes than any one is able 
to do in hours of close application. The principal 
advantages of steam are, that it will penetrate 
where an instrument will not enter, and where 
anything else would be ineffectual to accomplish 
the desired result. Journal boxes with oil cellars 
will get filthy in time, and are difficult to clean 
in the ordinary way; but, if they can be removed, 
or are in a favorable place, so that steam can be 
used, it is a veritable play work to rid them of any 
adhering substance. What is especially satis¬ 
factory in the use of steam, is that it does not add 
to the filth. Water and oil spread the foul matter, 
and thus make an additional amount of work. 

MIXTURE FOR CLEANSING RUSTY STEEL 

Tin putty, 10 parts; prepared buckshorn, 8 
parts; spirits of wine, 25 parts. Mix to a paste. 
Rub on the part to be cleaned and wipe off with 
blotting paper. 

HOW TO CUT A GLASS GAUGE TUBE 
Take a three-cornered file and wet it, hold tube 
in left hand with thumb and index finger at the 


248 


USEFUL KNOWLEDGE 


place where you wish to cut, saw it quickly two 
or three times with the edge of the file; then take 
tube in both hands, both thumbs being on the 
opposite side to the mark and about an inch«apart, 
then try to bend the glass, using the thumbs as 
fulcrums. 

Too much bearing surface in a journal is some¬ 
times worse than too little. 

Steel hardened in water loses in strength—but 
hardening in oil increases its strength, and adds 
to its toughness. 

Rule for roughly figuring on the coal in a bin 
or box—Multiply the length of the bin or box 
with its width and the product by the height of 
the coal in feet. Multiply the result by 54 for 
fine anthracite coal or by 50 for bituminous. The 
answer will be in pounds. Divide by 2,000 to get 
tons. 

If a leather belt is oil-soaked, sift Fuller’s earth 
(a mixture of clay and silicious matter) or pre¬ 
pared chalk on its face, and after a while remove 
it by scraping with a sharp edged stick. 

A little damp salt applied to the pulley side of a 
leather belt roughens it and prevents slipping. 

Oil is injurious to rubber belts, but when a rub¬ 
ber belt slips on account of dust and dryness, a 
little boiled linseed oil lightly applied on the pul¬ 
ley side of the belt will remove the trouble. 


ELECTRICAL MACHINERY 


ELECTRICITY 

Q.—What is electricity? 

A.—Electricity is the name for the cause of a 
large and important class of phenomena in nature, 
such as attraction and repulsion, heating, luminous 
and magnetic effects, chemical decomposition, etc. 

Q.—Is it a fluid? 

A.—It probably is not. Nobody knows exactly 
what it is. It is now supposed to be a quality, 
possessed to some degree by all or most substances, 
consisting in a peculiar movement or arrangement 
of the molecules. 

Q.—Is electricity a newly discovered power? 

A.—Its most simple effects were noticed by a 
Greek, Thales, in the sixth century before Christ. 
He observed that amber, when rubbed with silk, 
attracted light bodies, like bits of bran, cork and 
the like. (The Greek for amber is electron , hence 
the term electricity.) 

Q.—What is meant by positive and negative 
electricity? 

A.—It is found that gla*ss rubbed with silk 
attracts, while the silk repels. Sealing wax 

rubbed with silk repels, while the silk attracts. 

249 


2$0 


QUESTIONS AND ANSWERS 


The vitreous (glass) electricity is called positive, 
the resinous (wax) electricity is called negative. 

Q.—Is electricity always due to friction? 

A.—No, we have frictional (or statical ) and 
voltaic (or current ) electricity. The statical is so 
called because it is at rest. 

Q .—Which of the two is used in arts and 
mechanics? 

A.—The voltaic. 

Q.—How is it produced? 

A.—Either by a voltaic battery, or by revolving 
a coil of wire in the magnetic field between the 
poles of a steel magnet (electro-magnet), and by 
inducing the current by the action of another 
current or magnet. 

Q.—Is not this electricity just spoken of fric¬ 
tional? 

A.—It is generated by friction, but the induction 
changes it to current or voltaic electricity. 

Q.—What is an electro-magnetic field? 

A.—The spqce traversed by the lines of magnetic 
force produced by an electro-magnet. 

Q.—What is the principal difference between 
statical and current electricity? 

A.—Current electricity has little electro-motive 
force, but is very large in quantity. It has little 
power to overcome resistance (of a non-conductor), 
but it can do a great .amount of work. Statical 
electricity has the opposite qualities. 


ELECTRICITY 


2 5 * 


Q.—What kind of electricity causes lightning? 

A.—Frictional. It is in a state of high potential, 
and, therefore, has the power of overcoming great 
resistance and producing violent mechanical 
effects, but the quantity, and consequently the 
amount of electrical energy, is small. 

Q.—What is current electricity mostly used for? 

A.—For producing the electric light, for elec¬ 
tro-plating and for the transmission of energy. 

Q.—Is this manner of transmission of energy 
inexpensive? 

A.—Yes. It may be transmitted over miles of 
wire, which could be done in no other way, and 
some dynamos transform as high as 90 per cent of 
the mechanical energy used in revolving the 
armature into the energy of the electric current. 

Q.—What is chemical and thermal electricity? 

A.—Chemical electricity is produced by chemical 
action; thermal is produced by the application of 
heat to an arrangement of metallic plates. 

Q.—Does electricity pass through all substances? 

A.—No. Some materials, like rubber, mica and 
fiber, offer such high resistance that the current 
will take some other path. They are called non¬ 
conductors and are used for insulating conductors. 

Q.—What are the principal subjects considered 
under the head of current electricity? 

A.—They are the effects of the current in caus¬ 
ing chemical decomposition in electrolysis and 


252 QUESTIONS AND ANSWERS 

electro-metallurgy; in producing heat and light in 
a resisting medium; in the production of induced 
currents in a coil of wire; the measurement of 
electro-motive force (unit: one volt), of resistance 
(unit: one ohm), of the force of a current (unit: 
one ampere), and of working power (unit: one 
watt). 

Q.—How many kinds of current are dis¬ 
tinguished? 

A.—Three—continuous, alternating and multi¬ 
phase. The continuous current is a constant flow 
from the positive pole, as in chemical electricity. 
The alternating current is produced by a rotation 
of the two legs of a magnet opposite an armature, 
or, in modern machines, by a rotation of an 
armature between the two poles of a magnet. The 
multiphase current has more than one alternation 
during one revolution of the armature. 

Q.—Is there a simple way of detecting the 
nature of a current? 

A.—Yes. A magnetic needle introduced into a 
continuous current will assume a fixed position; 
in an alternating current it will swing from side 
to side; and with a multiphase it will revolve. 

Q.—How can it be determined which is the north 
or positive pole in an electro-magnet? 

A.—According to “Ampere’s Rule,” the experi¬ 
menter considers himself to be swimming head 
foremost with the current, along the wire, always 


ELECTRICITY 253 

facing the iron core; then the north-seeking pole 
will always be at his left hand. 

Q.—What other way is the positive or negative 
pole found? 

A.—First saturate a piece of white blotting 
paper with a solution of potassium iodide diluted 
in a glass of water, parts 1 to 4 . Place the blot¬ 
ting paper on one of the brushes, then hook one 
end of a piece of insulated wire, the ends of which 
are bare, to the switch and place the other end on 
the blotter where it touches the brush, and if it is 
the positive pole or brush the blotter on the under 
side will turn a brownish color; if it is the negative 
or south pole it will not affect it. 


ELECTRICAL TERMS 

Accumulator, or Secondary Battery—An ap¬ 
paratus for storing electrical energy produced by 
another apparatus. 

Alternate Current Dynamo—A dynamo in which 
the current rapidly alternates or reverses its 
direction from positive to negative. 

Ammeter, or Ampere Meter—An instrument 
for measuring the rate at which a current passes 
through a conductor. 

Ampere—The unit by which the flow of current 
is measured—so called after Ampere, a French 
scientist. 



254 


ELECTRICAL TERMS 


Ampere Hour—A current of one ampere flowing 
for one hour. When multiplied by the pressure 
in volts it gives the consumption of electrical 
energy in Watt-hours, 1,000 of which form the B. 
T. U. (Kilowatt). 

Ampere’s Rule—for finding the direction of a 
current—A magnetic needle, if placed near a 
current of electricity flowing from the observer 
who is facing the needle, is deflected to his 
left. 

Anode—The positive terminal of an electric 
source, in opposition to Kathode, the negative 
terminal. 

Arc—The bow of light produced by the electric 
current flowing between two carbon points 
(electrodes) which are slightly separated. 

Arc Lamp—A device for regulating and feeding 
the carbons of an electric arc, so that as the car¬ 
bons are consumed the distance between them 
or the length of the arc is continually preserved. 

Armature—That portion of a dynamo which 
revolves between the magnets and in which the 
electric currents are induced. 

Automobile—Machines that move automatically 
through electricity or any other force. 

Bare Conductors—Electric wires or conductors 
with no covering or insulation. 

Batteries, Primary—A set of cells for generating 
electric currents by chemical action, 


ELECTRICAL TERMS 


2 55 


Bitumen Insulation—A prepared bitumen com 
pound used for covering or insulating electric 
conductors. 

Board of Trade Unit (B. T. U.) 

—A measurement of electrical 
energy decided upon by the Board ( 
of Trade for the public supply 
companies to base their charges 
upon. It is equal to 1,000 Watt- 
hours, or about the amount of 
electrical energy consumed by 
seventeen 16 -candle-power lamps 
burning for one hour. 

Brush of Dynamo—An arrange¬ 
ment of copper wires, gauze or 
strips soldered together at one 
end, for collecting the current from 
the commutator of a dynamo. 

Buckling—A bending and dis- ... 

i| 

placement of the plates of an g "ivs* 
accumulator, caused usually by dis¬ 
charging the current too rapidly. 

Cables, E1 e c t r i c—U s u a 11 y 
applied to electric conductors, 
consisting of stranded wires, to dis¬ 
tinguish them from single wires. 

Calibration—Standardizing or correcting of any 
instrument to the standard value, such as volt¬ 
meter, ammeter, etc. 












256 


ELECTRICAL TERMS 


Candle, The Standard—A spermaceti wax 
candle, burning 120 grains per hour, taken as the 
standard of reference for measuring the lumi 
nosity, or candle power of any light. 

Carbons—For arc lamps, rods, or pencils, gen¬ 
erally made from powdered gas-coke, hardened 
into shape by baking, and used for the electric 
arc. 

Casing, Wood—A covering or sheath of wood, 
generally containing two grooves, used for the 
protection of insulated wires. 

Cathode—The negative terminal of an electric 
source. See Anode. 

Cell—A box or other receptacle containing the 
elements and solutions necessary for the produc¬ 
tion of storage of electrical energy. A number of 
such cells are termed a battery. 

Change Over Switch—A switch for changing 
electrical connections from one source of supply 
to another. 

Charging—Filling or storing an accumulator 
with electrical energy. 

Circuit—A system of metallic or other conduct¬ 
ing bodies placed in continuous contact and 
capable of conveying an electric current. 

Commutator—Bars of copper and sheets of 
isinglass to separate them, which form the ends 
of the armature coils, ^nd from which the current 
js collected. 


ELECTRICAL TERMS 


257 

Conductivity—The facility offered to the pass¬ 
age of electric currents through a substance. 

Conductor—A substance through which elec¬ 
tricity will pass, but applied principally to those 
in which very little resistance is offered to the 
passage of a current, such as copper wire. 

Continuous Current—A current from a dynamo 
or battery which does not vary in direction and 
flows continuously. 

Controller—An automatic magnetic regulator 
for a dynamo-electric machine. 

Converter — The inverted transformer or 
induction coil, used on alternating current 
systems. 

Coulomb—The unit of electrical quantity. 
That quantity of electricity which would pass 
in one second through a resistance of one ohm 
with a pressure of one volt. 

Current, Electric — The flow of electricity 
through any conductor. 

Creeping—A leakage of electricity over the 
surface of an insulating body, caused by a film of 
moisture and dirt, or deposit from evaporation, 
forming a conductor. 

Dielectric—Another term for insulator. 

Diaphragm—A plate or sheet securely fixed at 
its edges, as a drum head, and capable of being 
set in vibration, like a telephone diaphragm. 
Dimmer— A choking coil employed on trans- 


258 ELECTRICAL TERMS 

former circuits to regulate the potential. Used in 
theaters to turn the lights up or down. 

Distributing Board — A board from which 
branch wires or cables are led to various positions 
from main conductor. 

Dynamo—A machine for producing electricity 
by transforming mechanical work into electrical 
energy. 

Earth or Ground—Term used to denote the 
leakage of electricity (short circuit). 

Earth Return—A circuit in which the earth 
forms part of the conducting path. It is usually 
formed by connecting the ends of an insulated 
line, either to gas or water pipes, or to metal 
plates buried in the earth. 

Electric Motor—A machine similar to a dynamo, 
but used for conveying electrical energy into 
mechanical power. 

Electrical Energy—The capacity of electricity 
for doing work, whether for electric lighting or 
for power or traction purposes. It is directly pro¬ 
portionate to the amount of current and its pres¬ 
sure. Thus by multiplying the flow of current in 
amperes by the pressure in volts the amount of 
electrical energy is obtained in watts. 

Electricity, Thermal—Produced by the applica¬ 
tion of heat to an arrangement of metal bodies. 

Electrodes—The two terminals forming the 
positive and negative poles in a battery. 


ELECTRICAL TERMS 


2 59 


Electrolier—A device for suspending a group of 
incandescent lamps; the equivalent of chandelier, 
gasalier, etc. 

Electrolysis—The process of chemically separat¬ 
ing the component parts of any substance by 
means of electricity. 

Electrolyte—Any substance capable of under¬ 
going a chemical dissolution by an electric current. 

Electro-Magnet—A bar of soft iron temporarily 
magnetized by the influence of an electric current 
passing through a wire encircling it. 

Electro-Metallurgy—The science or process of 
electrically decomposing solutions or salts of 
metals. 

Electro-Motive Force (usually written E. M. F.) 
—The cause of the transfer of electricity, and 
therefore the force which supplies the pressure to 
an electric current. 

Electro-Plating—The depositing of metals by 
means of electricity upon the surface of another 
metal or other substance. 

Field, Electro-Magnetic—The space traversed 
by the lines of magnetic force produced by an 
electro-magnet. 

Filament of an Incandescent Lamp—The thread¬ 
like substance composed usually of vegetable 
matter (such as bamboo, cotton, paper, etc.), 
which by the application of intense heat has been 
carbonized. 


260 electrical terms 

Forming Plates—The operation of bringing the 
plates of accumulators into proper chemical con¬ 
dition. 

Galvanic Electrichy—Produced by chemical 
action; so termed after Galvani. 

Galvanometer—An instrument used in testing, 
for showing the flow of an electric current. 

Glow—A white, bright heat. 

Henry—The practical unit of self-induction. A 
secohm or quadrant. 

Horse-Power—To find the power of engine 
required to run a dynamo, multiply voltage by 
amperes, then multiply the answer by number 
of lights lit and divide by 746 . Answer in 
Watts. 

Hour Lamp—A service of electric current which 
will maintain one electric lamp one hour. 

Incandescent Lamp—A glass bulb or globe 
from which the air has been exhausted, contain¬ 
ing a carbonized filament which comes to a white 
glow on the passage of an electric current. 

Induced Current—Electricity produced by the 
influence that one magnetic or electrified body has 
on anothef not in contact with it. 

Induction—The influence that one magnetic or 
electrified body has over another produced by a 
dynamo. 

Installation—Plant. 

Insulation — The non-conducting substance ap- 


ELECTRICAL TERMS 


261 


plied to the surface of an electrical conductor to 
prevent leakage. 

Insulator—Any non-conducting material, such 
as guttapercha, india- 
rubber, china, glass, oko- 
nite, etc. 

JabloQhkoff — The in¬ 
ventor of the Jablochkoff 
candle, an arrangement 
of carbons placed side 
by side, and separated 
by a suitable non-con¬ 
ducting substance, such 
as kaolin, and used to 
form an electric arc. 

Kaolin—The finest of 
china clay. 

Kathode—See Cathode. 

• Kilowatt— 1,000 Watts. 

Mains — Copper cables 
or other means used for 
the purpose of conveying 
electricity, chiefly applied 
to the larger conductors incandescent lamp and 

, ^ SWITCH SOCKET. 

or cables. 

Megohm—A unit of resistance; equal to one 
million ohms. 

Meter, Electric—An instrument for measuring 
the amount of electrical energy used. 



262 


ELECTRICAL TERMS 


Milliampere—The one-thousandth part of an 
ampere. 

Motor—Any machine which may be used for 
imparting mechanical power. A dynamo running 
the reverse way. 

Negative—See Positive. 

Non-Conductor—Any substance which, resists 
the passage of electricity, chiefly applied to those 
in which this quality is strongly marked. 

Ohm—The unit by which the resistance offered 
to the passage of an electric current is measured; 
the legal ohm is the resistance offered by a column 
of pure mercury, 106 centimeters in length and 1 
millimeter square in cross-section; or the resist¬ 
ance offered by a copper wire 32 gauge, 10 ft. 
long (from Dr. G. S. Ohm). 

Okonite—Composition of tape and rubber 
mixed, to wrap joints, to insulate, etc. 

Parallel Wiring—Term used to express the sys¬ 
tem of electrical distribution, in which each lamp 
has its individual flow and return wires, no current 
passing through two lamps in series. 

Permanent Magnet — A piece of steel or 
loadstone containing enduring magnetic force, 
and requiring no electric current to mag¬ 
netize it. 

Photometer—An instrument for measuring the 
intensity of light. 

Pilot Lamp—A test lamp frequently used in the 


ELECTRICAL TERMS 263 

engine-room, serving to denote the E. M. F. of 
the current from the dynamo. 

Plugs, Safety-Fuse—The movable portion of the 
safety-fuse, containing the fusible wire. 

Plugs, Shoe—The movable portion of a shoe or 
small attachment, to which are attached the 
flexible wires in connection with the portable lamp. 

Poles—General term to express the positive 
and negative conductors in electricity, or the north 
and south extremities of a magnet. 

Positive and Negative—Terms hsed to dis¬ 
tinguish the polarity of wires in an electric 
circuit; the flow is termed the positive pole, and 
the return the negative. 

Potential—As heat tends to equalize between 
two bodies of different temperature, so' electricity 
tends to equalize between two points of different 
potential. As the difference in level between two 
water reservoirs connected by a pipe determines 
the velocity of the equalizing process, so the 
difference of potential determines the electro¬ 
motive force of the equalizing electric current. 
Another determining part is the resistance of the 
connecting conductor; as the diameter of the 
connecting pipe and friction are for the two watpr 
reservoirs. 

Primary Cables and Wires—In an electrical 
system of distribution where high pressure cur¬ 
rent is transformed to low pressure, all cables and 


264 


ELECTRICAL TERMS 


devices conveying the high-pressure current are 
termed primary. 

Resistance—The opposition afforded by any 
substance to the passage of electricity. 

Resistance Coil—A coil of wire used for creating 
a certain desired resistance to the passage of a 
current. 

Rheostat—An instrument consisting of one or 
more resistance coils for varying the resistance in 
an electrical circuit. 

Rocker—An attachment on the bearing of a 
dynamo to permit of the adjusting of the brushes. 

Safety Fuse, or Cut-Out—A device for auto¬ 
matically stopping the flow of electricity in case 
of accidents or defects in the conductors; a single¬ 
pole safety fuse controls only one wire, a double¬ 
pole controls both the positive and negative. 

Scaling in Accumulators—The formation of a 
deposit upon the plates which prevents the acid 
from acting upon them. 

Secondary Wires—The low-pressure coils in a 
transformer, which are acted upon by the primary 
or high-pressure wires. 

Series, Electro-motive—An arrangement of the 
metals, so that each is positive with reference to 
those which follow in the list, and negative to 
those which precede. In dilute sulphuric acid the 
order is zinc, lead, iron, copper, silver, platinum, 
carbon. 


ELECTRICAL TERMS 


265 


Series Wiring—Where the positive pole of each 
cell is connected to the negative pole of the next 
cell. In the multiple arc, all the positive poles are 
wired to one post and all the negative ones to 
another; 

Short Circuit—A term used to express any 
metallic or other connection formed accidentally 
between a positive and negative wire, by which 
the current may take a short cut, instead of com¬ 
pleting its journey through the lamp, motor, etc. 

Sunbeam-Lamps—Incandescent lamps of high 
candle power. 

Switch—An arrangement for breaking or com¬ 
pleting an electric circuit. 

Telpherage—A system of overhead transporta¬ 
tion of goods by means of cars running between 
two steel rails top and bottom of car from which 
an electric current is obtained to work motors 
fixed on one or more of the cars. 

Tension—The sanfe for electricity, as pressure 
for steam. 

Terminal—Attachment screw, by which a cur¬ 
rent enters or leaves any electrical apparatus or 
conductor. 

Thermo-Pile—A combination of certain metals 
coupled together so as to produce electricity by 
the application of heat. 

Three-Wire System—A system of distribution 
in which two dynamos and three wires are so 


266 


ELECTRICAL TERMS 


connected that the third wire serves as flow and 
return to the other two wires. Besides a consider¬ 
able saving in the cost of the cables, a constant 
potential service results. 

Transformer — An instrument for reducing 
or transforming a high pressure current to a low 
one, or the reverse. 

Transmission of Power — The operation of 
conveying or transmitting power from one point 
to another. 

Turbine—A machine for utilizing the force or 
fall of running water. 

Two or Three-Way Switch—A switch having 
two or three contact pieces attached to con¬ 
ductors, which by means of a movable handle 
permits the current to be sent into either con¬ 
ductor. 

Unit, Board of Trade. See B. T. U. 

Unit, of Current. One Ampere. 

Unit, of Electrical Energy. One Watt. 

Unit, of Pressure. One Volt. 

Unit, of Resistance. One Ohm. 

Volt—The unit by which the electro-motive force 
or pressure of current is measured. It is the E. M. 
F. that will cause a current of one ampere to flow 
against a resistance of one Ohm. The volt is 
based on the product of one Daniell cell. Named 
after Volta, an Italian scientist and inventor of the 
Voltaic column.. ’ ’ 


THE DYNAMO AND ITS PARTS 267 

Volt-Meter — The instrument for measuring 
the pressure or E. M. F. of a current. 

Vulcanized India Rubber — India rubber, 
treated with suphur, etc., to preserve and make 
it hard. To combine india rubber with sulphur 
by heat. 

Watt, The—The unit by which electrical work 
is measured. It is equal to the current of one 
ampere flowing at a pressure of one volt. 

The amount of energy is found by multiplying 
the amount of current by its voltage pressure. For 
instance, a current of 10 amperes with a pressure 
of 100 volts, represents 1,000 Watts. See B. T. U. 

Wire, Flexible—A conductor composed of a 
large number of fine wires stranded together, so 
making it flexible. 

Wires, Electric—Small conductors, other than 
the mains. 

THE DYNAMO AND ITS' PARTS AND 
ATTACHMENTS 

Q.—What is a dynamo? 

A.—The dynamo, or better, the dynamo-electric 
machine, converts energy (motion of piston and 
disc) into electricity by the aid of the permanent 
magnetism present in certain iron portions. The 
electricity generated then reacts on the iron, 
heightening its magnetism; the increased mag¬ 
netism again produces more powerful electrical 



268 


QUESTIONS AND ANSWERS 


effects, and so on, until a limit is reached. The 
lifnit depends partly on the velocity of motion 
partly on the quality and proportions of the iron 
and wire in the dynamo, and partly on the 
resistance throughout the circuit. 



Q. —What are the parts of a dynamo? 

A.—An electro-magnet M, M, M, which is 
made of two columns of soft iron, encircled by 
coils of insulated copper wire, and which are 
united together by cross pieces top and bottom. 














THE DYNAMO AND ITS PARTS 269 

Between the poles or magnet revolves the 
armature A, which consists of a number of coils 
of insulated wire wound around an iron core. 

The ends of each coil are connected to copper 
strips (segments, or bars) placed side by side, 
forming a cylinder known as the commutator C, 
from which the current is collected. Generally 
two sets of so-called brushes or collectors B are 
fixed upon the rocker (yoke) D, which remains 
stationary, unless it is necessary to adjust the 
position of the brushes around on the commutator. 
(See pages 273, 285.) Attached to these brushes, 
one set being positive and the other negative, are 
cables E, E, conveying the two main currents 
(positive and negative) generated to the switch at 
the top (side) of dynamo, by means of which con¬ 
nection can be made with the main supply cables. 
An attachment F, F to convey the current to the 
electro-magnet is at the top of the two magnet 
coils. G is the driving pulley. 

The armature should be kept up to the proper 
speed found stamped on field plate. The speed is 
known by a speed indicator and timepiece. Com¬ 
mutator should be kept quite clean and bright by 
wiping it occasionally with a rag when running. 
If necessary it may be cleaned with sandpaper 
before starting for regular run, the brushes being 
raised off the commutator. 

The brushes for service must be set firmly in 


270 


QUESTIONS AND ANSWERS 


their holders and rest well on the commutator so 
as to make good contact. They must be set 
exactly opposite each other and no brush wires (if 
made so) left straggling. 

The rocker yoke holding the brushes should be 
moved up or down, so as to adjust them to the 
neutral point, according to the amount of current 
the dynamo is supplying. When properly adjusted 
there should be no sparking. 

Q. —What is a commutator? 

A.—It consists of a number of metal cylinder 
segments insulated from each other by mica. 

Q.—What is the exact function of the com¬ 
mutator? 

A.—It serves to rectify, or send in o?ie direction , 
the vibrations or opposing currents created by 
the alternate passing of each pole of the armature 
before the north and south pole of the magnets. 

Q.—How is it done? 

A.—It is done in different ways. In some sys¬ 
tems, springs, sliding over the half cylinders, are 
so arranged that they always are one in positive, 
and the other in negative condition. In other 
systems the armature is rotated so rapidly (1,600 
revolutions per minute, and more) that the waves 
of current succeed each other at such short inter¬ 
vals, that they appear like a steady current, no 
break in continuity being perceptible to ordinary 
tests. 


THE DYNAMO AND ITS PARTS 271 

Q. —Does this rapid magnetization and demag¬ 
netization produce heat? 


A.—Yes, overheating of the dynamo is a draw¬ 
back of this system of commutation. 



Q. —What is the accumulator? 


A. —It is a battery of cells in which the electrical 
power is stored. It is also called a secondary 
battery. 

Q.—What is such a battery used for? 

A.—The wet battery (large cut) is used for 
storing electricity to maintain a limited number of 
lights after the dynamo has been shut down. The 
dry accumulator (small cut) is used for automobile 
vehicles, small lamps, etc. 










272 


QUESTIONS AND ANSWERS 



F.LECTRIC CYCLE LAMP AND POCKET ELECTK1C ACCUMl' ELECTRIC HAND LAMf 

ACCUMULATOR. LATOR. ACCUMULATOR. 


Q.—What is a rheostat? 

A.—It is an instrument for regulating or adjust¬ 
ing a circuit, so that any required degree of resist¬ 
ance may be maintained; a resistance coil. 

Q.—Give an ex¬ 
ample of the way in 
which the rheostat is 
used? See cut 

A.—When the dy¬ 
namo is first speeded 
to proper speed it 
shows a dull light 
and through the 
rheostat or controller the voltage is raised up to 
no, the proper voltage for incandescent lamps. 

Q.—What is a transformer? 

A.—It is used for tapping a low voltage circuit 
into a high voltage circuit, as in connecting an 
incandescent lamp to an arc light circuit. 

Q —What is a “step up’’ transformer? 






















THE DYNAMO AND ITS PARTS 273 


A.—It is used for the reverse, getting high 
voltage from a low voltage circuit. 

Q.—On what principle are transformers based? 

A.—On greater or lesser 
resistance. 

Q.—What is a converter? 

A. — The inverted trans¬ 
former, or induction coil, used 
on alternating current sys¬ 
tems. 

Q.—Are the same brushes 
used for dynamos and motors? 0 

A.—No. The motor brushes THB transformer 
are almost exclusively compressed carbon; on the 
dynamo copper plates or wires are used. 



Q.—How are the pointer and scale used? 

A.—They are attached to the rocker stud, and 
serve to secure a sparkless position of the 
brushes by adjusting the arrow to the scale every 













274 QUESTIONS AND ANSWERS 

time the load (number of lamps in circuit) is 
changed. 

Q.—What is a Daniell cell? 

A.—A zinc plate immersed in dilute sulphuric 
acid contained in a porous vessel, outside of which 
is a perforated copper plate surrounded by a 
solution of copper sulphate. The action is as 
follows: The reaction between the zinc and sul¬ 
phuric acid produces zinc sulphate and hydrogen. 
The latter, however, instead of collecting on the 
copper plate, unites with the copper sulphate* 
forming sulphuric acid and metallic copper. The 
former goes to keep up the supply of acid in the 
inner vessel and* the latter is deposited on the 
copper plate. The consumption of copper sul¬ 
phate is made good by a supply of crystals in a 
receptacle at the top. 

Q.—What is a gravity cell? 

A.—It is a modification of the Daniell cell, in 
which the porous vessel is done away with. The 
two liquids are separated by their specific gravities; 
the copper sulphate surrounds the copper plate at 
the bottom, and the zinc sulphate surrounds the 
zinc plate at the top. 

HOW TO MAKE TRACING-PAPER 

Place your sheets of double-crown tissue paper 
in one smooth pile, and apply to the top sheet a 
mixture of mastic varnish and oil of turpentine, 
equal parts in bulk, using a flat brush, 2 inches 
broad. Hang each sheet, when coated, over a 
line to dry. You may trace on this paper with ink. 



VARIETIES OF THE DYNAMO 


Q.—Is a continuous flow of current desirable for 
all electrical purposes? 

A.—Yes. 

Q.—Then, why is the alternate current used so 
much for traction and similar purposes? 

A.—Because it is very difficult and expensive to 
produce a continuous current of the required high 
voltage (2,000 volts and over). 

Q.—How high a voltage may be produced by 
the alternate system? 

A.—Theoretically, there is no limit. 

Q.—What is a magneto-electric machine? 

A.—It is similar to a dynamo, except that the 
fields are permanent magnets instead of electro¬ 
magnets. 

Q.—What is a compound dynamo machine? 

A.—One whose fields are wound with two coils, 
one of large wire, being in series with the arma¬ 
ture, the other of smaller wire in parallel with the 
armature. This arrangement makes the dynamo 
self-regulating. 

Q.—What is a multipolar dynamo? 

A.—A bi-polar dynamo has only one pair of 
field magnets, a multipolar one has more than 
one pair. 


275 


2 7 6 QUESTIONS AND ANSWERS 

Q.—What is an alternating current dynamo? 

A.—A dynamo without a commutator. The 
fields are usually separately excited, as a direct 
current is required for their excitation. 



ELWELL-PARKER ALTERNATE CURRENT ^JYNAMO. 


Q.—What is meant by “separately excited”? 

A.—The field coils receive the current for their 
excitation from some source other than their own 
armature. 

Q.—What is meant by closed-coil? 

A.—The coils are connected continuously to¬ 
gether in a closed circuit, being attached to 





VARIETIES OF THE DYNAMO 277 

successive bars of the commutator, as in the 
Gramme and most direct-current dynamos. 
When not connected continuously, although at¬ 
tached to successive bars of the commutator, as 
in the Brush or T. H. arc dynamo, they are termed 
open-coil. 

Q.—What is shunt? 

A.—A dynamo so constructed that the entire 
current must pass through the field coils, is called 
a series dynamo; where an additional path 
(external circuit) is provided, so that only a por¬ 
tion of the current passes through the field coils, 
this parallel connection is called shunt. The 
fields are “wound in shunt with the outside 
circuit.” 

Q.—What is meant by short-shunt? 

A.—When the shunt coils of the fields of a com¬ 
pound dynamo are connected to the brushes of the 
machine, not to the binding posts or external 
circuit as in the long-shunt. 

Q .—What is a “shunt and separately-excited” 
dynamo? 

A.—It is compound-wound, one field coil receiv¬ 
ing current from the armature, the other from a 
separate source. 

Q.—How many kinds of series dynamos are 
there? 

A.—Three, all compound, as follows: 

1. Series and magneto, in which the circuit of 


278 QUESTIONS AND ANSWERS 

a magneto machine is connected in series with its 
armature and fields. 

2. Series and separately-excited, in which the 
fields have two circuits, one in series with the 
fields and external circuit, the other being sepa¬ 
rately excited, used to maintain constant potential 
at the terminals. 

3. Series and shunt, one of the field coils of 
which is in series with the armature and outside 
circuit, the other in shunt with the armature. 

Q.—What is meant by synchronizing? 

A.—Modifying the phase of two alternating cur¬ 
rent dynamos so that they may be connected in 
parallel. 

Q.—What is the three-wire system? 

A.—A combination of Edison’s for the distribu¬ 
tion of electric current for constant potential 
service, in which three wires are used instead of 
two, one being a neutral wire. Two dynamos are 
employed. 

Q.—What is constant potential service? 

A. —An even flow of current. In a water pump 
the air chamber similarly renders the pressure and 
flow even or constant. See Potential, p. 263. 

Q.—What is the difference between a dynamo 
and a motor? ’ 

A.—The dynamo converts mechanical work into 
an electric current, which the motor then converts 
back into, or uses in, mechanical work. 


MANAGEMENT AND CARE OF A DYNAMO 


THE PLANT 

Q.—What rules should be observed in placing 
a dynamo? 

A.—It should be placed in a well-lighted, clean, 
cool and dry place, and so that it is easily access¬ 
ible from all sides. 

Q.-—What should not lie near a dynamo? 



Generator Panel: Front, Side and Back Views. 


A.—Iron, steel, bolts, nails, tools of any descrip¬ 
tion, or waste, filings or dust, as they may be 
attracted by the powerful magnetism or the cur¬ 
rent of air created by the revolving armature. 

279 
































280 questions and answers 

Q.—Where should the switch-board and fuse 
blocks be? 

A.—Like the engine, they should be so near 
the dynamo that the whole plant can be taken 



Feeder Panel: Front, Side and Back Views. 


in at one glance, but so far apart that there is no 
danger of a short circuit. 

Q.—Of what should the bases of all cut-outs, 
switches, lightning arrestors, etc., be made? 

A.—Marble, slate, or porcelain. 

Q.—How should connections be made? 

A.—Soldered and thoroughly insulated. 

Q.—What kind of wire should be used in damp 
places? 

A.—Rubber-covered wires. 





























THE CARE OF A DYNAMO 


28l 


Q •—Would you use metal staples in electric 
light or power work? 

A.—No. Use porcelain insulators. 

Q.—What is an insulator? 

A.—It is a non-conductor, preventing the cur¬ 
rent from leaving the wire. (See page 312.) 

Q .—In cleat work, what kind would be best to 
use? 

A.—Those with V-shaped grooves; they clamp 
firmly. 

Q.—How many cleats should be used to turn a 
corner or angle, and why? 

A.—Two, to make it neat and workman-like. 

Q.—Would it be safe and proper to use a bare 
wire in any part of the wiring throughout a build¬ 
ing? 

A —No. All wires should be properly insulated. 

Q.—How do you test the insulation of a wire, 
to see whether it affords the required resistance? 

A.—It should be tested to not less than 250 
Megohms per mile in dry places and 600 Meg¬ 
ohms per mile in damp places. The test must be 
taken with an electro-motive force of not less than 
400 volts after the insulated cables have been in 
water at 60 degrees Fahrenheit for 24 hours, and 
with one minute’s electrification. 

Q.—What should be put in a line, between the 
cut-out switch and the street where the wire 
entered the building? 


282 


QUESTIONS AND ANSWERS 


A.—Loops of wire known as drip loops. 

Q.—What style cf belting should be used for a 
dynamo or motor? 

A.—It should be a light double, endless and 
rivetless one. 

Q.—Why should the belt be endless and not 
laced? 

A.—Because every time the laced joint passed 
over the dynamo pulley the lights would fluctuate 
(flicker). 

Q.—If the belt is endless, how is the slack taken 
up? 

A.—Nearly all dynamos and motors are provided 
with a frame and belt-tightening apparatus com¬ 
prised of one center or two side screws and 
foundation slides on which the dynamo rests; 
with these the dynamo or motor can be forced 
back and the belt tightened. 

Q.—How much should a belt be tightened? 

A.—Enough to prevent extreme slipping. 

STARTING THE DYNAMO 

Q.—What should be done every day before 
starting a dynamo? 

A.—The dynamo tender should examine the 
binding posts, the commutator and brushes, also 
see that the contacts are clean and firmly tight¬ 
ened by the set screws. Any dust and dirt should 
be most carefully removed with soft rags and a 


THE CARE OF A DYNAMO 283 

bellows, as they cause the majority of all the 
troubles and annoyances. 

Q.—What rules should be observed in starting 
the dynamo? 

A.—Always start the machine to running with 
the main switch open and the brushes raised from 
the commutator, so all the working parts can be 
seen; be sure that the rheostat is at zero. Then 
drop the brushes on the commutator, then see that 
the voltage is correct on volt-meter. If the 
brushes spark, rock the brush holder quadrant 
forward or backward around the commutator until 
a sparkless place is found, then close the main 
switch. When running drop a little oil on the end 
of finger and rub in the palm of hand, then pass 
the finger gently over the commutator lengthwise. 

Q.—How high would you cause the volt-meter 
needle to rise? 

A.—The proper voltage for incandescent lights 
is no volts. If run up to 115, there is danger of 
burning out the filaments. 

Q.—What rules must be observed in disconnect¬ 
ing the dynamo? 

A.—In disconnecting the dynamo after it has 
been used for charging the accumulators or supply¬ 
ing lights, etc., the engine should be eased down, 
dynamo switch opened, and the brushes raised 
from the commutator to cool, also to be free in 
case the armature was turned the reverse way. 


284 QUESTIONS AND ANSWERS 

The copper brushes should be filed to one bevel, 
also kept clean and free from oil, copper dust, etc. 

RUNNING THE PLANT 

Q.—How and when would you test the circuit? 

A.—It should be tested every day for grounds, 
by means of the detector, galvanometer or a mag¬ 
neto bell. 

Q.—If there was a ground, how would you 
locate it? 

A.—By disconnecting the. circuit in different 
places, and testing each section separately until 
located. 

Q.—Give various reasons for excessive sparking 
of commutator and brushes of a dynamo or motor? 

A.—Poor condition of the brushes and holders; 
faulty adjustment of brushes; surface of the com¬ 
mutator rough or covered with dirt and grease; 
the insulation of one field magnet coil injured and 
the coil short-circuited in itself. 

If one magnet is excited more than the other, 
one brush will spark more than the opposite one, 
in the same way as if improperly adjusted. 

Two .or more segments of commutator short- 
circuited. 

Dynamo or motor overloaded. Overloading will 
also cause considerable heating of the armature 
and fields. Overloading of the dynamo, or motor, 


THE CARE OF A DYNAMO 285 

may be caused by poor insulation of the external 
circuit, thus causing a considerable amount of 
current to escape fronTone pole to the other. 

Grounding of the external wires, which fre¬ 
quently happens in rainy weather. 

In arc lighting, lamps may be fed by too strong 
a current; in incandescent lighting, too many lamps 
may be put on the leads. 

Q.—Name the different causes of the eating 
away of the segments of a commutator? 

A.—Too much tension, too- much contact sur¬ 
face, brushes not set properly, or not far enough 
around on the commutator. 

Q.—What will cause flat spots on the face of 
commutator? 

A.—Badly soldered armature wire connections, 
also soft spots in the copper segments. 

Q.—How would you know when brushes have 
not enough contact or pressure on commutator? 

A.—By a peculiar snapping noise. 

Q.—-What is the effect of a brush being too long, 
or pressing too hard? 

A.—It will cut the commutator, emitting strong 
spattering sparks. 

Q.—How can the brushes be made to press 
harder or lighter on the commutator? 

A.—By adjusting the brush holders. 

Q.—How are brushes moved on commutator? 

A.—By the yoke (quadrant). (See page 273.) 


286 


QUESTIONS AND ANSWERS 


Q.—Why are they moved around on the com¬ 
mutator, and when? 

A.—When more or fewer amperes of electricity 
are necessary for lights, power, etc. 

Q.—How are the different kinds of brushes 
adjusted? 

A.—Practically all alike. They should be set 
at a bevel of 45 ° to the commutator. Each brush 
should cover at least one segment and two insula¬ 
tions to make the current as nearly continuous as 
possible. 

Copper wire or copper leaf brushes are filed to 
a 45 0 bevel and the commutator wears them 
to a concave. Carbon brushes are concaved by 
putting coarse sandpaper on the commutator, 
rough side up, and by drawing it to and fro. 

Q.—Where should the brushes be set? 

A.—At neutral (opposite) points. 

Q.—How would you make a copper brush? 

A.—Cut the strips the width of the opening in 
the brush holder, and take so many of them that 
the brush will pass through the holder easily, 
and solder them together at one end. The same 
for wire, gauze and other copper brushes. 

Q. —How thick should a carbon brush be? 

A.—One-half thicker than the commutator bar 
to make it strong enough. 

Q.—Is it safe to touch the two opposite brushes 
(positive and negative) at any time.while running? 


THE CARE OF A DYNAMO 287 

A.—No, for if the motor or dynamo be 
grounded (short-circuited) the full voltage would 
be received and cause either paralysis or death. 

Q.—When a motor or dynamo becomes very 
hot, to what would you lay the trouble? 

A.—It being overloaded, or poor connections. 

Q.—How can stationary motors be reversed? 

A.—By changing (crossing) the wires on the 
yoke or fields, also reversing the brushes. 

Q.—Suppose the twine covering the armature 
wires near the commutator segments happened to 
unravel whi’e running, what would you do? 

A.—Open switch and after motor or dynamo 
has stopped remove the remaining twine. 

Q.—Would it not interfere with the machine? 

A.—No. It is there to keep out as much dust as 
possible from in between the armature wires. 

REPAIRS 

Q.—What causes the insulation of one or more 
coils around the armature to char and crumble off? 

A.—Excessive heat caused by short circuit, poor 
connections, overloading, and cotton waste, etc., 
being attracted at the end of the dynamo and 
pressed between the armature and pole pieces. 

Q.—-In what way will the waste injure the 
armature?, 

A.—By scaling off the insulation from the wire 
in some places or bursting the metal bands encir¬ 
cling the armature. 


288 QUESTIONS AND ANSWERS 

Q.—Do these injuries extend below the outside 
layer of wire? 

A.—Sometimes, but not very often. 

Q.—Can the wires be insulated without being 
taken to a repair shop? 

A.—Yes, by carefully lifting one wire at a time 
just high enough to wrap it with silk tape, and 
thus insulate it. 

Q.—What causes the field magnet to short- 
circuit and burn the insulation? 

A.—By getting parts of the field wire in contact 
with the iron core. 

Q .—What should be done in such trouble? 

A.—Unwind the wire until the damaged part is 
reached, and after insulating it properly, it should 
be wound back on the cores. 

Q.—How are field magnets wound and un¬ 
wound? 

A.—By placing the field horizontally between 
the two centers of a turning lathe. 

Q.—What would you do after having wrapped 
and insulated all the injured parts of an armature? 

A.—Drive the wires back into their positions by 
means of a hard wood block and hammer, after 
which give them two or three good coatings of 
shellac varnish. 

Q.—If the injury was below the outside layer, 
what should be done? 

A.—Take the armature to a regular shop and let 


THE CARE OF A DYNAMO 289 

them do the repairing, as they have the proper 
tools to do the work. 

Q.—Suppose you had to replace an old com¬ 
mutator with a new one, how would you proceed 
to do it? 

A.—Take the armature out from between the 
poles, and place the two ends of the shaft on 
wooden horses. Mark the wires leading from the 
armature to the commutator by attaching little 
tags with numbers, to make sure of the proper 
place of each wire after taking off the commutator. 
Then disconnect these wires from the correspond¬ 
ing copper bar of the commutator, either by 
unscrewing the set screw, or unsoldering the con¬ 
nections by means of a hot soldering iron. After 
this is done remove the commutator, clean the 
shaft and connections and put the new com¬ 
mutator carefully in its proper position, and 
connect the armature wires in proper turn to the 
corresponding copper bars of the commutator by 
means of set screws, or hard soldering. Great 
care must be taken not to short-circuit any part of 
the commutator with drops of solder. 

Q.—Why do electrical engineers and linemen 
wear rubber gloves and rubber soles? 

A.—Because rubber, like glass, is a non-con¬ 
ductor of electricity. Live wires should never be 
touched without one or the other, as instant death 


may occur, 


MEASUREMENTS OF ELECTRICITY 


Q.—What is a dyne? 

A.—The unit of force. The force which, in one 
second, can impart a velocity of one centimeter 
per second to a mass of one gramme. 

Q.—Why are these terms not given in U. S. 
measurements, such as ounces and inches? 

A.—Because scientists all over the world use 
the decimal system, and electricity has been 
developed by scientists exclusively. 

Q.—What is an erg? 

A.—The work done in moving a body through 
a distance of one centimeter with the force of one 
dyne. A dyne centimeter. Ten million ergs = 
one joule. The joule is the practical C. G. S. unit 
of electrical energy or work. (C. G. S. = cen¬ 
timeter—gramme—second.) 

Q.—What is a watt? 

A.—The unit of electric work or power, equal 
to one joule per second. 

One H. P. == 746 watts. 

The number of watts is numerically equal to 
the product of the current passing, times the 
voltage which produces that current. 1 volt 
times 1 ampere = 1 watt; 3 volts times 3 amperes 

9 watts, etc. 

A kilowatt is 1,000 watts. 

290 


MEASUREMENTS OF ELECTRICITY 291 

Q.—What is a coulomb? 

A.—The unit of electrical quantity. That 
quantity of electricity which would pass in one 
second through a resistance of one ohm with a 
pressure (force) of one volt. 

Q.—What is an ampere? 

A.—The unit of electric current. That rate of 
flow which would transmit one coulomb per 
second. 

Q.—What is an ampere-hour? 

A.—The equal of one ampere flowing for one 
hour, or 3,600 coulombs. 

Q.—What is an ohm? 

A.—The practical unit of electrical resistance. 
A resistance through which an electric current of 
one ampere will flow under a pressure of one 
volt. 

The legal ohm , now internationally adopted, 
equals the resistance of a column of mercury 106 
centimeters in length, having ah area of cross- 
section of one square millimeter, at o° C., or 32 0 F. 

A section of wire having a resistance equal to 
the legal ohm is used as a “standard ohm.” 
1000 feet of Jjj-inch copper wire has a resistance 
of very nearly one ohm; a mile of common iron 
telegraph wire has a resistance of about 13 ohms. 

A megohm = one million ohms. 

Q.—What is the Law of Ohm? 

A.—The strength of a continuous current (C) 


292 QUESTIONS AND ANSWERS 

is directly proportional to the electro-motive force 
(E) in the circuit, and inversely proportional to 
the resistance (R) in it. It is, therefore, the e. 
m. f. divided by the resistance. C =— ; E = C X 

R; R = —. 

c 

Q.—What is a volt? 

A.—The practical unit of electric pressure, or 
electro-motive force. The pressure required to 
move one ampere against one ohm. The volt is 
based on the product of one Daniell cell. 

Q.—What similarity is there between electrical 
terms and steam terms? 

A.—The volts may be compared to pounds of 
steam pressure; the resistance to friction; the 
wire to the pipe; the coulomb to the quantity of 
steam passing through the pipes; the ampere to 
the rate at which the steam passes; the watt to 
the amount of work performed (H. P.). 

Q.—What difference do you make between 
“force” and “power”? 

A.—In common language, they are used as 
equivalents, but in science the following distinc¬ 
tion is made: 

Force is the cause of a change, such as from 
rest to motion, or in condition, etc.; power is the 
rate of the expenditure of energy. Electricity, 
steam, gravity, expansion, etc., are forces; we 
speak of horse-power, candle-power, gross and net 
power, etc. 


measurements of electricity 293 

Q-—How much of a H. P. is required to main¬ 
tain a steady light for a 16-candle-power incandes¬ 
cent lamp? 

A.—About one-tenth, or 10 lamps to a H. P. 

Q.—How many volts for an arc light? 

A.—220. 

Q.—Can arc lights and incandescent be run on 
the same circuit? 

A.—Yes, by the use of the transformer. 

Q.—How is the efficiency of a dynamo deter¬ 
mined? 

A.—By dividing the electrical energy produced 
by the mechanical energy expended in driving 
the dynamo. 

Q.—How do you arrive at the amount of elec¬ 
trical power spent? 

A.—By multiplying the amount of current by 
its pressure. For example, a current of 10 
amperes with a pressure of 100 volts represents 
1,000 watts (1 kilowatt). A current of 20 amperes 
with a pressure of 50 volts represents the same 
power (1,000 watts). 

Q.—What is meant by the B. T. U.? 

A.—It means the consumption of electrical 
energy of one thousand watts in one hour. 

Q.—How are the electric currents measured? 

A.—Either chemically or mechanically. 

Q.—Explain the chemical system? 

A.—It is based on the simple fact that one 


294 QUESTIONS AND ANSWERS 

ampere of electricity will deposit from sulphate of 
zinc, under standard conditions, a definite weighty 
of metal. This type of meter is a small electro¬ 
plating battery through which a certain proportion 
of the current is carried -the proportion being 
accurately determined by the relative sizes of the 
meter wires and the shunts—with the result that 
one of the two plates is decreased and the other 
increased in weight, according to the amount of 
current consumed. 

Q.—Where and how is the meter placed? 

A.—It should be p’aced in a clean, dry place 
and connected to the inside service with moisture- 
proof wire. It must always.be protected by a 
service cut-out; never placed between the cut-out 
and the street service. It should be in a place 
not likely to freeze, also where the inspector can 
have easy access to it. The meter should be 
screwed fast to a well-seasoned board, not less 
than i inch thick and well-covered with asphal- 
tum against the wall. Never place more lights 
on a meter than it is intended to carry. 

Q.—What test is made, and how is it made? 

A.—It is necessary to find the positive clips and 
mark them. For this two things must be known: 

Which side of meter is connected to street, and 
which of the two outside wires is positive. 

The first is found by tracing the conductors or 
opening the circuit. 


MEASUREMENTS OF ELECTRICITY 295 

The second, by testing with a blotting paper 
saturated with a solution of potassium iodide. 
With the moistened paper in hand press it 
against the upper and middle binding posts. 

A brown mark will appear where the paper 

Meter Fed on Right Side. 

(See cuts A and B.) 

‘A”—When top post gives 
brown mark, right hand 
clips are positive. 

“B”—When middle post 
gives brown mark, left hand 
clips are positive. 


Meter Fed on Left vSide. 

(See cuts C and D.) 

“C”—When top post gives 
brown mark, left hand clips 
are positive. 

“D”—When middle post 
gives brown mark, right 
hand clips are positive. 


touched the positive post. By following rule the 
positive clips can be determined. The clips are 

















296 MEASUREMENTS OF ELECTRICITY 

at the top of meter and the chemical bottles set 
under them. 

If the center wire is not brought into the meter, 
the lowest post must be used for the middle in 
using foregoing rules. 

All positive clips should be carefully marked. 
The positive plate can be known by it being next 
to the head of the bolts which bolt the two plates 
together. 

Sometimes the positive plate has a tag attached, 
which prevents mistakes. 

Q.—Explain the mechanical meter? 

A.—Of these there are many varieties, those 
most in use being the Thompson-Houston watt 
meter and the Westinghouse or Schallenberg 
ampere meter, both of which are small motors 
driven faster or slower as the demand for current 
is greater or less, and communicating their action 
to a train of wheels with dials like those of a gas 
meter, so that they may be verified by burning a 
given number of lamps for an hour and compar¬ 
ing the dials at the beginning and end of the 
time. The meter record is taken usually once a 
month, and the bills are based upon these records 
with as much certainty as though electricity 
were visible. 


THE MOTOR AND CONTROLLER 


Q. —What is an electric motor? 

A.—The reverse of the dynamo, used for con¬ 
verting electricity into mechanical work. 

Q. —When is the work of an electric motor at 
its maximum? 



*6VTTvr;0US CUPRENT ELECTRIC-MOTOR. 


A.—According to the “law of Jacobi,” when the 
counter E. M. F. is equal to half the E. M. F. 
expended on the motor, or the impressed E. M. F. 

Q .—What are stationary motors used for? 

A.—For running elevators, machinery, dyna¬ 
mos, etc. 

Q.—Where does a stationary motor get its 
power from? 

297 





298 THE MOTOR AND CONTROLLER 


A.—From a dynamo, or generally from a three- 
wire system set of dynamos. 

Q .—What voltage, amperes and speed has a 15 
H. P. motor? 

A.—Generally 220 voltage, and any amount of 
amperes it may need and 1,600 speed per minute. 

Q.—What different systems of using electricity 
for traction are in use? 

A.—The overhead trolley, the underground 
trolley, the storage battery and third-rail systems. 



Q.—How are the brushes set on the commutator 
of a car or engine motor? 

A.—Directly against the commutator and op¬ 
posite, instead of aslant as on stationary’ motors. 

Q.—What voltage and H. P. are the motors of 
elevated roads? 




























Railway Motor. 

THIRD RAIL SYSTEM WITH SLIDING 
FEEDER SHOE 


SIDE VIEW 
OF 

MOTOR TRUCKS 




TOP VIEW 


299 























































































































3 °° 


QUESTIONS AND ANSWERS 


A.—Generally 2,000 volt type and 100 H. P. 

Q.—How many are usually placed under a car? 

A.—Two—one at each end of car, so as to avoid 
the need of a turn table. 

Q.—What system is generally used? 

A.—The third-rail system. (See page 299.) 

Q.—Can the car be run in both directions from 
either end? 

A.—Yes, by reversing the motor through the 
controller box. 

Q.—How is the electric current transmitted from 
the third rail to the controller and motor? 

A.—By a shoe sliding on the third rail. The 
shoe may be raised from the rail by a short ful¬ 
crum lever in the controller room, thus breaking 
the circuit. 



Q.—How is the motor of a surface trolley car 
suspended and geared to the wheels? 










THE MOTOR AND CONTROLLER 301 

A.—It is suspended with springs and a frame 
between the wheels and truck. 



The armature axle is geared to the wheel so 
that the armature pinion turns about four times to 
a single turn of the wheels. 

THE CONTROLLER 

Q.—What is a controller and its duty? 

A.—It consists of two switches (see cut, page 
302), each having its own separate operation to 
perform. The controlling cylinder (switch) No. 
2 proper is used simply to make the different com¬ 
binations required to obtain the proper regulation 
of the speed of the car. The second switch, or 
small handle, is also of a cylindrical form, but is 
used for either breaking the circuit or reversing 
the motor, either forward or back. 

Q.—Can a controller be compared to a rheostat? 

A.—Yes, its function of controlling the speed of 
the car can be compared to the working of the 
rheostat in increasing or decreasing the resistance. 

Q. —Will switch No. 1 of the controller cut off 
the current if moved? 






















3 02 


QUESTIONS AND ANSWERS 


A.—Yes, the slightest movement cuts the cur¬ 
rent entirely off. 

Q.—How many notches has the current switch? 
Name them? 

A.—Three—go ahead, back up, center cut-out. 




Q.—How is the resistance provided on an elec¬ 
tric controller? 

A.—A considerable amount of resistance is pro¬ 
vided in the shape of bands, fingers or strips of 
iron or nickel steel. 

Q.—How is this resistance subdivided? 























THE MOTOR AND CONTROLLER 303 

A.—Into a considerable number of parts so that 
it can be cut down gradually. 

Q.—How many notches has a controller dial 
plate, and what is their purpose? 

A.—Generally 7, and they are there to indicate 
the increase of speed gradually and uniformly by 
continually lowering the resistance of circuit. 

Q.—When the motorman moves the large handle 
No. 2 around on the dial (notch plate), what does 
it do? 

A.—It connects a coil of wire on the motor with 
trolley (feeder) wire each notch it is moved, 
s Q.—Suppose the controller handle No. 2 stood 
in the seventh notch and the current switch No. 1 
was suddenly turned on, what would be the result? 

A.—The fuse strips would blow, or melt. 

Q.—What are cut-out plugs or strips? 

A.—They are fusible wire and are used to save 
overcharged or heated wires from melting. 

Q. —To what could the above be compared so as 
to be easily understood? 

A.—To an attempt at starting a steam engine 
suddenly at full speed instead of gradually turn¬ 
ing on the steam with throttle. 

Q.—Compare the principle of controller box 
and coils of motor with the steam engine? 

A.—It is the same as placing the reverse lever 
in center notch so valve equally covers both steam 
ports, then opening the steam valve full, this 


304 


BALDWIN AND WESTINGHOUSE 


acting as the current switch, and the reverse lever 
as the controller switch. When ready to start 
drop the reverse lever "or controller down one 
notch; if more steam or current is required drop 
it another notch, and so on until the full power 
or current is passing into cylinder or motor coils 
(fields). 



The Baldwin and Westinghouse Electric 
Engine has solved the problem of a locomotive 
running 120 miles an hour. •* 

In appearance this new wonder does not betray 
its qualities. The motors are incased, so that 
hardly any mechanism is in sight. The electric 
headlight and the pilot alone disclo.se its character 
as a motor car or locomotive. 

The locomotive weighs 150,000 lbs. and is 37 
feet long over the pilot. 

The frame is made of 10-inch rolled steel chan¬ 
nels, covered by a one-half inch rolled steel plate 
over the entire floor, giving enormous strength to 
resist blows in collisions, etc. 

This frame is carried on two trucks, with all the 
modern devices of springs, for swinging motion 





















ELECTRIC ENGINE 


305 


and free movement. The trucks are built very 
strong and they are of the swiveling type, so they 
may go around any curve passable for an ordinary 
freight car. 

The geared connection between the axles and 
the electric motors permits of any gear ratio 
desired. 

The driving wheels may be connected by par¬ 
allel rods for pulling heavy trains, as such rods 
would not permit one pair of wheels to slip with¬ 
out the other. 

The motors are directly beneath the car floor, 
between the two trucks, and are “iron-clad” con¬ 
sequent pole motors. 

They are entirely encased in thin steel shells, 
so as to be protected from all injury under 
normal conditions of service. 

The armatures are laminated, being made up 
of thin slotted discs of steel. In the slots the 
armature wires are placed. The commutators are 
of the best forged copper with mica insulation. 
The motors have the highest grade of insulation. 
Power is furnished by the third-rail system. 

At both ends is a controller. The path of the 
current may be divided so as to pass to both 
motors independently, or it may be sent through 
one motor to the other. 

The braking system has some unique features. 
The compressed air-brake is used. The engineer’s 


3°6 


HEATING AND COOKING 


valve is of the standard Westinghouse type. 
When the handle of the brake valve is put at 
“emergency” for a sudden stop, pneumatic action 
breaks the circuit at the same time as it applies 
the brakes.—A .special reversing switch acts on 
the motors.—The automatic air-pump is driven by 
electricity, its special motor being directly con¬ 
nected and without gear. 

The interior of this locomotive is that of an 
observation car, and very handsome. 

Our 120 miles an hour locomotive is ready for 
us, but we are not quite ready for it. Before we 
can risk flying across the country at such speed, 
all grade crossings must be abolished and the 
whole present R. R. signal system must be 
changed. Signals are now about a mile apart, 
while the new locomotive cannot stop within less 
than one and a half miles of clear way. 

Electricity for Heating. —To fit heating and 
cooking utensils for the use of electricity, a thin 
film of enamel or cement is spread over the outer 
saucepan, griddle, kettle or heater. Then iron, 
platinum or other high resistance wire is laid 
zigzag over it, with copper wire connections made 
to the two ends; and more of the cement or 
enamel is spread over the wires so as to com¬ 
pletely embed them. When enamel is used the 
apparatus is put in a kiln and burnt on similar to 
the ordinary iron cooking utensils. In both 


BY ELECTRICITY 


307 


methods the film of enamel or cement insulating 
the heating wires is put on so thin and is so good 
a conductor of heat that the heat generated by 
the electricity is rapidly conveyed to the utensil 



CK1DDLE. CQEKBEtHKAIBR. 

to be heated. Electricity can thus be sent through 
the wires without fear of overheating them. This 
would not be possible if they were exposed to the 
air, which does not conduct heat, but radiates it. 








308 stationary motor and connections 

To start motor, quickly throw in switch 4. Then 
move rheostat-handle 3, slowly over the arc, until 
stopped by magnet 10, which holds it while motor 
runs. The nearer the handle approaches the mag¬ 
net, the larger a number of high-resistance wire coils 
in the rheostat box transmit the current, which has 
full flow when handle reaches magnet. To stop 
motor, throw switch 4 out, and move handle 3 off 



The motor, 1, in the cut is series wound, one 
pole connected with two binding posts of revers¬ 
ing switch, 2; the other pole connects with handle, 
3. 5, 5 1 are safety-fuses, 6 is the volt-meter, 7 the 

ampere-meter, which at 8 connects with rheostat 
graduation arc. Fuse 5 1 connects with third 
binding post on switch, 2. By throwing lever, 9, 
to the left, the direction of the current, and with 
it the motion of the motor, is reversed. 























































































ELECTRIC WIRING 


CONDUCTIVITY 

No part or particle of any substance on earth 
can ever get lost. It may change its form, but it 
cannot get away from the earth. There is now 
exactly as much water on earth as there was one 
thousand years ago, not even one drop more or 
less, while there is, of course, a constant change 
in its distribution over the globe, in the proportions 
of its three forms (gas, liquid, ice), and in its 
combinations with other substances. Heat con¬ 
sumed in expansion, etc., is called “latent heat.” 

So, also, electricity, like any other force, cannot 
get lost, but it may change its form. When an 
electric current meets resistance its quantity is 
decreased , and the difference can be indirectly but 
accurately measured by the increased temperature 
of the resisting substance. Current electricity 
not transmitted is converted into heat. 

The several metals vary as much in their power 
of transmitting electric currents (conductivity) as 
they do in other respects. Silver and copper 
possess the greatest conductivity, tin and lead the 
smallest. The same fact may be stated thus: Tin 
and lead offer the greatest resistance to an electric 
current, silver and copper the least. Any sub¬ 
stance that offers great resistance is called a bad 
309 


3i° 


ELECTRIC WIRING 


conductor; the less the resistance (or, the greater 
the conductivity), the better a conductor is the 
substance. 

Conductivity is nearly zero for glass, sulphur, 
resin; it is very low for most liquids and for gases. 
It varies not only with varying temperature, but 
also with varying tension, torsion, or pressure. It 
stands in proportion to the cross-section area of the 
conductor (wire). 

The following table shows at a glance that in 
the list of the metals named the heat evolved by 
an electric current increases in the inverse ratio 
as the conductivity decreases. The conductivity 
of gold is % of that of copper, the heat evolved is 
§ or times that of copper. The conductivity 
of tin is *4 of that of copper, the heat evolved is 6 
times as large: 


Conver- Conduct- 
sion ing 

to heat. power. 

Silver. 6 to 120 

Copper. 6 to 120 

Gold . 9 to 80 

Zinc.....18 to 40 


Conver- Con duet - 
sion ing 


to 

heat. 

power 

Platinum... 

30 

to 

24 

Iron. 

30 

to 

24 

Tin. 

36 

to 

20 

Lead. 

■ 72 

to 

IO 


Silver wire conducts 120 units out of 126, losing 
6; iron wire conducts 24 out of 54, losing 30; lead 
conducts 10 out of 82, losing 72. 

Silver, copper and gold are excellent for con¬ 
ducting strong currents; platinum and iron are 
used where very light currents are required, as 
in telegraphing; lead is used where great resist- 









ELECTRIC WIRING 


311 

ance is desirable to check too strong a current, as 
in safety-fuses; platinum is used in incandescent 
lamps because its expansion in heat is equal to 
that of glass; zinc and tin find minor employment, 
as stated further on. 

For traction and electric lighting very strong 
currents are needed, and the conductors are, there¬ 
fore, made of copper wire of a size proportionate 
to the rate of flow desired, gold and silver being 
excluded by their costliness. 

Copper can be procured in sufficient quantity, is 
therefore cheap enough, and is very durable and 
flexible. The purer copper is the better. The 
law does not allow an alloy containing less that 96 
per cent of pure copper for electrical purposes. 

Copper that has become brittle from some cause 
can be made soft again (annealed) by heating it 
dark cherry and plunging into cold water. 

INSULATION 

As dry air is a non-conductor, bare copper 
wires will conduct a strong electric current without 
losing any of it (without leakage). This is why 
telegraph, arc light and trolley wires are left 
without a covering. 

Moist air, all wet substances and water, are 
excellent conductors, and by one of the principal 
laws of electricity an electric current returns to 
its source by the easiest possible path, or along 
the line of least resistance. 


3 12 


ELECTRIC WIRING 


The ground, whether earth or lake or sea, is 
always ready to serve as the easiest and shortest 
path back to the source, and in order to have the 
current flow through all the wires of the circuit in 
undiminished force, and to provide against any 
portion of it taking a short circuit , the wires 
exposed to possible dampness, contact with water, 
or the like, are insulated, that is, they are covered 
with a dampness-proof, water-proof, non-con¬ 
ducting material. 

Such materials are glass, ebonite, paraffin, 
shellac, india rubber, gutta percha, sulphur, silk, 
porcelain, etc Some of these are suitable in some 
places and conditions, and others in others. 

Iron and porcelain are used for supporting bare 
wires. For telegraph cables gutta percha is used, 
which, however, is easily affected by heat, and 
cannot be used for insulating electric light wires 
carrying a large voltage. Instead, a fibrous 
matter (jute and the like), steeped in a resinous or 
bituminous compound, is used. India rubber 
(vulcanized to make it harder and more durable) 
is considered the best insulator for house wiring. 

To prevent decomposition of the rubber by the 
copper, the copper wire is usually coated with tin, 
which also makes soldering the joints easier. 
Then a cover of india rubber is put on, then a 
second cover of vulcanized india rubber. The 
third covering consists of india-rubber-coated 


ELECTRIC WIRING 


3*3 

tape (okonite), and over this tarred flax is 
braided and coated with a preservative compound. 

When the wire is so insulated, the electric cur¬ 
rent finds it easier to travel the length of it foi 
thousands of miles than to escape through the 
insulation, one-sixteenth or one-eighth of an inch 
thick. But remember, wherever the insulation is 
faulty or injured, admitting water or contact with 
any other good conductor, there the current escapes 
and returns by the shortest route to the source. 

Aside from the loss in lighting power, such 
defects are frequently the cause of disastrous 
conflagrations or of death. House wiring should 
be entrusted to experienced, skillful and con¬ 
scientious men only. 

For test of insulation, see page 281. 

SIZE OF WIRE 

Two considerations determine the proper size of 
wire to be used in a circuit: The wire must be 
thick enough to carry an electric current of the 
desired voltage at the desired rate of flow, and on 
the other hand, to avoid unnecessary expense, it 
must not be thicker than necessary. 

If the “Wire is too thin, a portion of the current is 
converted into heat (see page 309), and the hot 
wire becomes a source of great danger. The fire 
insurance inspectors insist on this point, and 
rightly so.^ Of course, the light furnished by too 
thin a wire is very poor. 


3H 


ELECTRIC WIRING 


CONNECTIONS 

A joint or connection must be solid, that is, it 
must not offer any more resistance than the wire 
itself, and must, therefore, be made with the 
utmost care. The second requirement is, it must 
be damp proof. 

The strands of copper are first cleaned by scrap¬ 
ing, then interlapped or scarfed, another wire is 
wound around the joint (especially in the case of 



large cables), and the whole is soldered. This 
gives a so-called hard joint. Then insulation is 
put on with equal care, first india rubber, and 
then okonite (india rubber tape), making a solid 
and dampness-proof insulation. 

ARRANGEMENT OF CIRCUITS 
The plan for the wiring of a building should be 
given great care and skill, requiring much experi¬ 
ence. 

First, find the point at which the main circuit 
from the dynamo or supply-wire will be most 
conveniently divided up into a number of smaller 
circuits. A fau’t is easily located in a small circuit 
and cannot disturb the service except in its own 
circuit. A “ central distribution board ” is 
erected, and from this a small special circuit leads 



ELECTRIC WIRING 


315 


to each lamp, or, in a large building, cables run to 
a number of branch distribution boards, with which 
then the lamps are connected. 

It is best to connect each lamp with the distribu¬ 
tion board by two wires (parallel wiring). If all 
the lamps are strung along one common circuit 
(series wiring), all the lamps will be affected by 
any little irregularity, and the distribution of cur¬ 
rent is uneven. These disadvantages far outweigh 
the saving in the first expense of installation. 

PLACING THE WIRES 

The greatest care should be taken to keep the 
wires absolutely free from dampness or water, 
since they establish at once a short circuit (earth, 
ground, leakage), and a portion or all of the 
electric current returns by the nearest path (by 
wall or pipe, or the like, and the ground) to the 
source. 

Another great cause of annoyance to be guarded 
against, is a short circuit by leakage from one wire 
to another through defective insulation, crossed 
wires, etc. The electric current, finding its way 
through dry dust, lint, rubbish, or wooden parts, 
heats them to the point of ignition, and a fire is 
the result. 

In placing the wires, neatness of appearance, 
safety from leakage, and protection from fire are 
the three points to be kept in mind. 


3 l6 


ELECTRIC WIRING 


Wires without casings should be 6 inches apart 
for mains, and 2% inches for smaller sizes. 

Metal or glass tubing is a good protection 
against gnawing rats or mice, but insurance 
inspectors do not look upon them with favor for 
high-voltage circuits. 

The most serviceable casings are of well- 
seasoned hard wood, grooved. The fillets sepa¬ 
rating the grooves should be 1^ inches in width for 
mains, 1 inch for main branches, y 2 inch for 
smaller branches. The inside of wood casings 
should be painted with a fire-proof paint or com¬ 
pound, and the wires packed in with asbestos or 
silicate cotton. 

For chandeliers twin wires are generally used. 
They should be handled very carefully, and 
properly protected with cut-outs. 

cut-outs ' 

What the safety-valve is for the boiler, the cut¬ 
out or safety-fuse is for the electric circuit. It 
consists of a short lead or tin wire of a size propor¬ 
tionate to the greatest quantity of current required 
for the circuit. If the curient increases beyond 
that point, the tin or lead wire, unable to transmit 
more than so much of the current, converts the 
excess into heat and melts (is blown), thus break¬ 
ing the circuit. 

The cut-out is a guarantee, therefore, against 
overloading the wire from any cause, short circuit, 


ELECTRIC WIRING 


317 


crossing wires, or negligence of dynamo attendant. 

The best place for the cut-outs is on the distribu¬ 
tion board, where the small circuits are connected 
to the mains. The circuits can thus be easily 
disconnected by removing the safety-fuse. For 
special purposes cut-outs are placed wherever 
desirable. 

THE SOCKETS 

Incandescent lamps receive the current from 
contact pieces in the socket of the “shoe,” or 
‘ ‘plug, ” or in a socket swinging on the circuit wires. 

Such plugs are frequently distributed along the 
walls of the rooms, for the sake of attaching a 
portable lamp to either one of them, wherever it 
may become desirable. This is a great con¬ 
venience. 

The socket is either a screw socket or a “bayo¬ 
net’ ’ socket. The latter is simply pushed in and 
turned around one-eighth, to make connection 
with the circuit. In the screw socket connection 
does not take place until the lamp is screwed in as 
far as it will go. 

To avoid the handling of the lamps when the 
current is to be turned on or off, a key or switch is 
provided. This key should never be placed any¬ 
where between full-off and full-on, not even for a 
moment, because in a partial connection the con¬ 
tact pieces will get heated and grave consequences 
may result at once or later on. 


THE ELEMENTS OF ALGEBRA 


By Prof. O. H. L. Schwetzky 

Q.—What is arithmetic? 

A.—The science, of numbers, or the science of 
numerical equivalents. 

Q.—What does it teach? 

A.—It teaches how to calculate or compute 
quantities by the means of numbers. 

Q.—W r hat is algebra? 

A.—Sir Isaac Newton called it “universal 
arithmetic,” meaning by this term, that algebra 
teaches the rules which apply to any and all 
numbers. 

Q.—What is one of the principal differences 
between arithmetic and algebra? 

A.—In arithmetic we have only io characters 
with which to*work: o, i, 2, 3, 4, 5, 6 , 7, 8, 9— 
and which, besides, have a limited meaning, 
variable by position only. In algebra, quantities 
of every kind may be denoted by any characters 
whatever. 

Q.—What are the characters mostly used in 
algebra? 

A.—The known quantities in each case are 
generally denoted by the first letters of the 

318 


THE ELEMENTS OF ALGEBRA 


319 


alphabet, a , b y c, etc., and the unknown quantities 
to be found are represented by the last letters of 
the alphabet, z , y, x, w, etc. 

Q.—What do these characters represent? 

A.—They represent any number chosen. 

If we assume a to represent 9, and b to repre¬ 
sent 3, then a + b=i2; and in a-(-b = c we 
would put c = 12. 

In a — b = c we would have c=6; in a X b = c, 
c would be =27; in a -7- b = c, c would be 
= 3- 

Ina-i-b=c-7-x, x is the required answer, a, b 
and c being known quantities. 

Q.—What signs are used in arithmetic? 

A .—Plus (+) for addition, minus (—) for sub¬ 
traction, times (X) for multiplication, by (-5-) for 
division, and equals (=) to show equality. 

Q.—What signs are used in algebra? 

A.-(-, — and =, as in arithmetic. The X is 

rarely used. Instead of a X b the form a b is em- 

a 

ployed, or a . b . Instead of a-rb we write 
Q.—Name another difference. 

A.—In arithmetic any operation that is readily 
performed is at once executed and the result sub¬ 
stituted, as 10 for 7 + 3, 3 for 10—7, 21 for 3X7. 
7 for 21-5-3; but i n algebra this is not done: a + b 

is called a sum; a — b is a quantity equal to the 

a 

excess of a over b; a b is a product; ^ is a quotient; 
( a + b) (c + d) is the product of the two sums 


320 


QUESTIONS AND ANSWERS 


a -f- b and c + d; a (b -j- c) is the product of a and 

the sum b - 4 - c; a ( —) is the product of a and the 

b \ c ' 
quotient — , etc. 
c 

Q.—Explain the use of the parenthesis, (), 
further? 

A.—It means that the term enclosed in the 
parenthesis is to be treated as one quantity. If 
a = 9, b = 8, c = 4, and d =3, then (a-f-b) (c-fd) 
=(9 + 8) (4 + 3)= 17 X 7= 119; a(b+c) = 9 X 12 
= 108 ; a J = 9 X 2 = 18. 

Q.—Are there no definite numbers used in 
algebra? 


A.—Yes. a + ais written 2a; ab-}-ab-|-ab = 
3 ab, etc. The definite numbers in this case are 
called numerical coefficients, or for short, co¬ 
efficients. 

a X a is written a a or a 2 , which is read ‘ ‘ a 
square.” a X aX a is written a 3 , which is read 
‘‘a cube,” etc. In this case the figure indicates 
how many times a quantity is to be multiplied by 
itself, and is called the exponent. 

Q. —In what relation does a stand to a 2 ? 

A.—It is the square root of a 2 . 

Q.—What is the meaning of a — b -j- 
— (2 ab -j- d) -|- 6 ac ? 

A.—That depends on the definite numbers to be 
substituted for the characters. If all the -j- quan¬ 
tities (positive quantities), a+^^ + 6ac added 


THE ELEMENTS OF ALGEBRA 32 I 

together give a larger quantity than the —quanti¬ 
ties (> negative quantities), b + 2 ab -|- d added to¬ 
gether, then the answer is positive, otherwise it 
will be negative. 

Q.—How can a quantity be negative? 

A.—In the case of bookkeeping it would mean 
that there is that much deficit or loss; in traveling 
it would indicate that distance back of a certain 
point instead of forward; on a thermometer or 
steam gauge it would indicate so many degrees 
below zero instead of above, etc. Plus means 
“above zero,” or “more than nothing,” minus 
means “ below zero,” or “ less than nothing.” 

Q.—What is the difference between a — b-J-c 
and a — (b -f- c) ? 

A.—In the first case b is to be subtracted from 
the sum of a and c; in the second case the sum of 
b and c is to be subtracted from a. The difference 
becomes clear by substituting definite numbers: 
20 — 9+4 = 15; 20 —(9+ 4) = 7. 

Q.—What is the meaning of a — (b + c) = a — 
b —c? 

A.—It means that additions and subtractions 
may be performed in any order. We may either 
subtract the sum b + c from a, or we may subtract 
first b from a and then subtract c from the 
remainder. The result is the same. 

Q.—Can you further illustrate the meaning of 
the minus sign ? 


3 22 


QUESTIONS AND ANSWERS 


A.— i. a-(-b = c — b 

a + 2b = c 

Taking — b away on one side is the same as 
adding -J-b, because -|-b — b = o. To keep the 
two terms at the sides of the = sign of the same 
value, we must add -f- b at the other side, too, 
which gives 2 b. 

2. a (—b) = —ab 

This signifies that “ multiplication by a negative 
quantity” (—b) means “starting from the zero 
point in the opposite direction .” If John has 
$500 assets, and Frank has ten times as much 
liabilities , he owes $5000. Also: If John owes 
$500, (— a), and Frank owes ten (b) times as 
much, he owes (— a) b = — ab, or $5000. 

3. ( —a) ( —b) =+ab 

This is the reverse of the above (2). The same 
principle applies. If John is $500 short, and Fred 
has ten times as large an amount of cash on 
hand, he has $5,000. Expressed as a rule, this 
simple truth presents itself as follows: 

Minns multiplied by minus produces plus, 

or, in other words, the product of 2 negative 
factors is positive. 

Q.—Can you further illustrate this rule? 

A.—1. A rich man said to his son: “I will 
make you the owner of a fortune 8 times as large 
as your present indebtedness.” The son con- 


THE ELEMENTS OF ALGEBRA 


323 


fessed that he owed at that moment $7,000. To 
make good his promise, the father had to pay the 
debt and give his son $56,000 besides. 

2. One ship sailed 200 miles due east from a 
port, while another steamed 3 times as far due 
west. They were consequently 800 miles apart, 
one being 200, and the other 600 miles, from the 
port, in opposite directions. 

3. An open siphon, one arm of which had a five 
times larger inside area of cross-section than the 
other, was provided with a scale, and filled with 
water to the zero point of the scale. A piston was 
introduced in the wider arm, and pressed down, 
until the water surface in this wider arm stood at 
3 inches below zero. Where was the surface in 
the other, smaller arm? Ans. (—3) (—5) = + 15. 



Q.—-What is the meaning of a| 


A.—It means that multiplications and divisions 
may be performed in any order. 

Q.—What advantage does algebra give? 

A.—It gives short characters instead of long 
numbers, and tedious multiplications, etc., are 
avoided, as no such operations need to be 
executed, except in the answer, where the given 
values are substituted. 


/ 


THE TRACTION ENGINE 

A traction engine is a locomotive for common 
roads, and by throwing the driving wheels out of 
gear is converted into a stationary engine. 



As a traction engine it is steered by a worm 
gearing, which turns a winding shaft, on which a 
chain is wound and unwound, drawing one or the 
other front wheel back, according to the direction 
in which the engine is to run. The engineer steers 
by turning a hand-wheel controlling the worm 
gearing. 

The driving wheels have V-shaped projections 
on their rims to prevent slipping. They get their 
motion through differential or compensating gears 
from the engine. (S6e cut page 326.) The motion 
of the engine is reversed through a special device, 
a single eccentric reversing gear, or through a 
reversing rack. (See pages 330, 331). 

324 










THE TRACTION ENGINE 325 



For turning the curves of a road one of the 
drivers is loose on the shaft, so that it may run a 
longer or shorter distance than the other driver, 
without straining the axle or connections. For 
running on a straight road, the loose driver is 
made solid with the 
shaft by inserting the 
key A into slot B. 

As a stationary 
engine (the drivers 
being thrown out of 
gear), the pulley- 
face fly-wheel (or a 
friction clutch wheel, 
see page 326), fur¬ 
nishes the power by 
means of a belt. 

The rear axles and 
brackets of all good 
traction engines are 
placed back of the 
will be well distributed between the fore and 
aft wheels. Short axles riveted to the sides of 
the firebox are very dangerous. 

DIFFERENTIAL OR COMPENSATING GEAR 

The differential or compensating gear is 
arranged as seen in the cut: A is a large bevel 



firebox, so that the weight 























326 THE TRACTION ENGINE 

wheel (loosely set on the axle), carrying three 
pinions, B, so distributed over it that they 

together engage 
the ground wheel 
by meshing either 
with C or D, ac¬ 
cording as the 
engine is to travel 
forward or back¬ 
ward. C is bolted 
to the main drive- 
wheel ; D is keyed 
on t h e axle. A 
gets its motion 
from the engine 
through the in¬ 
clined shaft and the 
bevel pinion, E. 

FRICTION CLUTCH FLY-WHEEL 

The fly-wheel of a traction engine must allow of 
being thrown in and out of gear easily. One of 
the most convenient de¬ 
vices for this purpose is 
the friction clutch shown 
in the cut. 

The wheel has diam¬ 
etrically placed a driving- 
arm, A, to which is cast a 
sleeve, B, surrounding 
the axle of the wheel. 

The end of B carries the 
pinion C, keyed to it at 
D. Both ends of the driv¬ 
ing arm A have a cast- 
iron shoe, E, loosely 
bolted to them. The bolts 
are solid with A. These 
shoes are hollow and 
filled with hard - wood 
blocks with a surface curved to correspond 
exactly with the inside surface of the wheel rim. 

















THE TRACTION ENGINE 327 

turned true. The free ends of the shoes are pro¬ 
vided with a toggle-joint (or turn buckle joint), 
G, G, by which the wood is pressed firmly against 
the wheel rim, when the fiy-wheel is to be 
en £ a g e d- The toggle-joint is worked by throwing 
the collar F, which loosely fits around the sleeve 
B, toward the wheel. This is done by means of a 
lever within easy reach of the engineer, but not 
shown in the cut. 


CROSS-HEAD 

A is the piston rod with threaded end. B is the 
piston lock-nut, C is the cross-head frame. D, D 
are the slide blocks, E,E are the cap screws which 
hold the slippers (slides), D, D, to the cross-head 
frame. F, F are the adjusting screws for taking 
up the wear of the slides. This is done (about 
once a year) by slightly slacking out the bolts E, 
E, and screwing in the screws F, F, until the lost 



motion is taken up. G is the small end of the con¬ 
necting rod containing the brasses, adjustable by 
means of a screw bolt, H, engaging with a 
beveled block in the strap, said bolt being locked 
in position by jam-nut K. The cross-head pin, L, 
can be removed by unscrewing the nut from the 
pin and driving the pin out of the cross-head frame 
by means of a hammer and a wooden block. 















3 2 8 


THE TRACTION ENGINE 


DIMENSIONS AND HORSE-POWER OF TRACTION ENGINES 

Their speed is about 250 revolutions a minute. 


Ten-inch Stroke 
Simple High-Pressure 
Engine. 

Ten-inch-Stroke Compound 
Tandem. 

Horse 

Diameter 

Horse 

Diameter in inches. 

Power. 

in inches. 

Power. 

HighP.Cyl. 

Low P. Cyl. 

9 

7 X 

12 

5 ^ 

8 X 

12 

8 X 

15 

6 ^ 

9 

15 

9 

20 

7 

10 

20 

10 

25 

7 % 

11 


TANDEM COMPOUND CYLINDERS AND VALVE 
MOTION 

The Tandem Compound Traction Engine does 
not differ much from the plain single cylinder 
engine, in operation, or in the care it requires. 
Where the work (load) amounts to the full horse¬ 
power capacity of the engine, the tandem com¬ 
pound is economical, otherwise it is wasteful. 

The accompanying cut shows the very simple 
and compact arrangement of the two cylinders 
(one high and one low pressure) and the slide 
valve. The cylinders are cast separately and 
bolted together at U. The partition R is cylinder 
head for both cylinders, is held in place by jam 
bolts (Y), and at S the piston rod passes through 
its center. The packing is metallic and does not 
need adjustment or renewal. One piston rod 
carries the two pistons, A, B. By unbolting at U, U, 
the interior of the two cylinders is reached easily. 

Only on the larger or “low pressure” cylinder is 
there a steam chest, valve seat, etc. In order to 
connect with both cylinders, the slide valve and 
seat are arranged as follows: Steam for the boiler 
enters through H into X, a chamber formed by the 
hood enclosing the slide valve. This hood and the 
slide valve proper are one casting, and move 




















THE TRACTION ENGINE 329 

together in the steam chest, M. The passages I, 
I communicate with M. From X the live steam 
passes through L into E in the high-pressure 
cylinder. At the end of the stroke, X and K com¬ 
municate and live steam enters from X through 
K (see dotted lines) into D at the other end of the 
high-pressure cylinder, reversing the piston 
motion. The expanded steam in E exhausts 
through L into the receiving chamber, M, and 
from there passes through I and N into G in the 
low-pressure cylinder. The steam expanded in 
D exhausts through K into M, and passes from 



there through I, P into F. P and N finally carry 
the steam exhausted from the low-pressure 
cylinder off through O. Port J in M serves to 
admit live steam to facilitate starting the engine. 
After starting, it is closed. 

The low-pressure cylinder must be larger than 
the high-pressure cylinder, because the expanded 
steam, exhausting from the latter into the former, 
is so much weaker than live steam that it requires 
more piston area to work on, to furnish the same 
pressure as the live steam exerts on the smaller 
piston area. The proportion of the areas is closely 
calculated by experts; roughly it may be said to 
be 1:2. See table, page 328. 

For more explicit information on compound and 
other engines see pages 96, 104 and 133. 

































33 ° 


THE TRACTION ENGINE 


Some engineers have asked why the valve was 
not worked directly by the piston rod, by means of 
a lever of the proper kind and proportion. (See 
leverage, page 241.) In the beginning the valve 
was worked in that crude way, and, at the very 
first, by hand. The necessity of economy, how¬ 
ever, in the consumption of steam has led to the 
devising of eccentrics, link motion, compound 
engine, single eccentric, etc. 

SINGLE ECCENTRIC, VALVE AND ENGINE 
REVERSING GEAR 

For general information about the eccentric, see 
page 116; link motion, page 144. 

A traction engine must necessarily have the 
most simple possible attachments. A very simple 
and ingenious valve and reversing gear is shown 
in the cut. 

There is only one eccentric. To the eccentric 
strap, which carries the valve rod, a roller is 
pivoted a little above the valve rod pin. The 

roller runs in a guide, 
the position of which 
is regulated by the re¬ 
verse lever, to which 
it is connected by a 
“reach rod.” Chang¬ 
ing the angle of the 
guide reverses the en¬ 
gine, or it may simply 
shorten or lengthen 
the travel of the valve 
and thereby change 
the point at which the 
steam is ‘ ‘cut. off. ’ ’ 
Besides its extreme 
simplicity, this device 
has the "further great 
advantage that it 
makes the lead of the 
valve “constant.” that is to sav, the lead does 
not vary with the travel, as it does in link motion. 
The valve gives a quick, full opening at exactly 



THE TRACTION ENGINE 


331 


the right moment, admitting steam promptly at 
the dead points. Also, it cuts off quickly, giv¬ 
ing quick expansion. 

To reverse, the lever is thrown back to the 
furthest notch on the quadrant. To stop, the 
lever is placed in the center notch. 

By holding the lever between the center notch 
and one of the other notches, the stroke of the 
slide valve may be set at any desired length short 
of its extreme travel. This is done by economical 
engineers, when the load is light. 

The whole gear is so simple and durable that no 
skill is required to run it, or to replace and adjust 
it. The eccentric has its center almost directly 
opposite the crank pin, so that the roller will stand 
exactly over the center of the guide, when the 
engine is at either dead center. This renders it 
easy to find the correct position of the eccentric. 

To set the valve, the eccentric rod is then 
adjusted so as to give equal lead at both ends of 
the valve. 

REVERSING RACK 


For throwing the eccentric into the reverse 
position, the reversing rack shown in the accom¬ 



panying cut is used on simple or single cylinder 
engines. Where the eccentric is cut away in the 
cut, the arrow shows the reversing rack. 








33 2 


THE TRACTION ENGINE 


STACKER GEARING AND TURNTABLE 

A, A is the upper frame; B, B is the lower 
frame. C is the lower frame chair bracket, with a 
central hub, and the pocket D, in which a collar 
turns, that is attached to the upper frame chair 
bracket E. The center gear shaft turns in the 
lower frame hub and in the upper frame collar, 



and is geared below (miter gear F) to the main 
shaft, G, driven by pulley H, and above (miter 
gear I, K) to the sprocket wheel shaft L. M is the 
shaft box. N is the bracket for the pin which, by 
means of the lever O, serves to clutch the three- 
wheel gear P, P, P, with the main shaft G, around 
which it fits loosely. When so engaged the pinion 
Q at the other end of the sleeve engages pinion R 
and the shaft S, at the other end of which there is 








































THE TRACTION ENGINE 


333 


a bevel spur wheel, T, driving U and V in opposite 
directions. The reversing spool, W, serves to 
throw shaft X into gear with either U or V. W is 
worked by means of the lever Y. Z is a universal 
joint, enabling shaft a and worm b to be thrown 
out of gear with the turntable d by the lever c. 
The turntable d is attached to A, A, pivots around 
the central shaft in the collar in D, and has a ball¬ 



bearing, E, E, attached to the lower frame. The 
shaft L drives the working shaft f by means of the 
sprocket wheels g, h , h. The three pulleys on 
shaft f drive the different parts by belting. 

Lever O starts or stops the stacker; lever c 
starts or stops the turntable d; lever Y controls 
the direction in which d turns. When the turn¬ 
table is thrown out of gear the stacker may be 
swung around by hand. 


























334 


THE TRACTION ENGINE 


THE STACKER 



The cuts show a straw 
stacker, both folded and in 
operation. The folding and 
unfolding are done by hand 
or steam power. 

A carrier, 24 feet long, 
delivers the straw from the 
hopper of the 
threshing ma¬ 
chine to the 
stacker. The 
stacker carries 
the straw to 
the desired 
height and 
dumps it on 
the stack. 



The mechanism of the turntable, reversing gear, 
etc., are fully described on pages 332, 333. 







JOURNAL-BOX BABBITTING 


335 


Standard Babbitts 

Martin’s 

Nickel. 

Copper. 

Antimony. 

*a 

H 

Zinc. 

Total. 

High Speed Babbitt... 

IO 

16 

4 

70 


IOO 

Medium or Common... 

. 

4 

6 

90 


IOO 

Machinery Bearings... 


88 


12 

. 

IOO 

Muntz Metal. 


6o 



4.0 

IOO 

German Silver. 

33>4 

33/4 

. . . 

' 

33 ^ 

IOO 

White Brass. 


IO 


10 

80 

IOO 

Fine Yellow Brass. 


66 



34 

IOO 

Gun Metal for Valves, 






etc. 


90 


10 


IOO 

Journal Brasses for 






Rods, etc. 


8o 

... 

j 7/4 

2^ 

IOO 


In melting babbitt metal care must be taken 
not to burn it by overheating. Melt a part first 
in small chunks, and add remainder gradually. 
As soon as all melted, remove from fire and skim 
off the dirt. If heated beyond the melting point 
the softer components evaporate and leave the 
mass in a pasty condition. 

When about to babbitt a journal wrap one 
thickness of common writing-paper smoothly 
around the bearing, fastening it in place with 
twine wound around in a regular spiral line three- 
sixteenths of an inch apart. The paper keeps the 
babbitt from getting chilled by the journal. 
It will, therefore, have a fine surface, and will 
also fit just right without any scraping. The 
twine leaves nice oil grooves. 

Before pouring the metal through the oil-hole, 
make sure the journal is level and in central posi¬ 
tion. By means of two pasteboard rings fitting 
the journal, the ends of the box are closed, using 
putty or soft clay. A high funnel of clay is made 
around the oil-hole to facilitate the pouring in of 
the babbitt, and to increase the pressure, so as to 
have the babbitt fill the box perfectly. 



























LAIRD & LEE’S 

HIGH GRADE 

MECHANICALWORKS 

For Engineers, Machinists and 
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Printed on Good Paper, Thoroughly Illustrated and £ 
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t The Mechanical Arts Simplified— 497 

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Book—Stiff silk cloth, red edges, 
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Manual — Leather, stained edges, 
gold stamped title, pocket, flap and 
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The Mechanic’s Complete Library— 570 

pages; illustrated; stiff silk cloth, 
red edges, $1.00; morocco, marbled 
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Sample Copies Sent Postpaid on Receipt of Price. 
1 Also Full Description of Each Book. 

♦ LAIRD & LEE, 263 Wabash Av.,Chicago 




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N 






































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